While gathering parts for my 5.0 EFI install I happened across a two speed electric fan from a 2004 Jeep Liberty, part number 55037669AE. This Liberty did not have the towing package. With the towing package the Liberty will have a different electric and a mechanical fan. The shape looked simple enough to make fitment easy and the depth was only about 4 ½” which was as short as I have seen any others.

After comparing it to my Ron Davis radiator I found that only minor trimming would be required to seal it to the radiator. Other Bronco radiators would probably have a similar fit.

Here’s a little more detailed view. Some minor trimming was also required at the upper radiator mount areas.

As you can see the fan shroud completely covers the radiator core with about ¼” to ½” extra over the tanks. This will prevent the fan from rubbing holes into the core tubes.
To mount the fan I used the radiator’s shroud mounting flanges at the top and bottom along with some ½” x ½” aluminum angle and some ¼”-20 bolts and locknuts . These photos show the bottom mounting.

The top is similar but the angle is reversed. I found it necessary to use captive speed nuts on the top four bolt holes. Can’t get to the inside once the fan is on the radiator.

I didn’t have the mating plug for the fan connector so I replaced it with a 3-pin Weatherpack connector. If you get the fan from a wrecking yard be sure to grab the other side of the connector also. The fan side of the connector is at the top. The black wire gets connected to ground and 12 volts on either of the blue wires will provide low speed. 12 volts on both blue wires will give you high speed.

I mounted two relays and a terminal strip on the inner fender just behind the battery to power the fan. The 12V control wires for the relays both run inside to a control panel.

I made a control panel for the fan and mounted it in the speaker opening of the dash. The amber LED will light if the fan is off (disabled). The green LED lights when the fan is actually running. No lights are on when the fan is enabled in automatic mode but not running. The LEDs are from Radio Shack, part numbers 276-272 and 276-271, $1.99 each I’ve wired it so automatic mode will only operate with the key on, manual mode will operate at any time.

Wiring for the switch panel is shown here. You’ll need two DPDT ON-ON miniature switches and one SPDT ON-ON miniature switch. I used some switches that I’ve been holding on to for years but Newark has part number 98K4949 for $1.46 each and 98K4963 at $1.10 each.

In order to have an automatic mode I needed to install a temperature controlled switch. I used an adjustable thermostat (upper thermostat) from an electric water heater. I found it at Lowes for about $14, item #: 26358. I removed the unneeded upper portion of the thermostat and used an ohmmeter to determine which contacts to use. You want the normally open contacts that close as temperature exceeds the set point. I mounted the thermostat on the lower radiator hose close to the radiator.

The thermostat works surprisingly well during most driving conditions and is easily adjustable for turn-on temperature. It does have some time delay between when the upper engine reaches temperatures above normal and when the switch closes. This will cause my engine temp to swing between 190 degrees (195 degree thermostat) and 215 degrees during very steep uphill climbs or prolonged idling. During these conditions I can select the manual fan mode and the fan will run continuously, keeping the temperature at a steady 190 degrees. Eventually I will go to a top mounted fan switch to prevent this hysteresis. This will only involve installation of the new switch and re-routing of the existing thermo-switch wiring. I have not found it necessary to use the high speed setting yet even during strenuous off-roading sessions on hot days. On the flat, open road the fan does not switch on at speeds over 35 mph. Also the fan is so quiet that I can’t hear it with the engine running from inside. I should also add that in automatic mode the fan speed is determined by the position of the Hi-Lo switch.
Installed, I have 3/16” clearance between the fan and the explorer serpentine water pump snout. It is possible to trim the plastic back of the fan housing a small amount to provide another ¼” of clearance if needed. I haven’t done this and don’t see that it’s necessary for my application.

The top, bottom and sides fit very nicely to the radiator tanks and overall it looks like factory fit. After a month of testing this fan and control circuitry I am very pleased with the operation of it. I’ve taken it on some very steep 4-low crawling hill climbs and it has performed flawlessly.

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Many modern vehicles with trailer towing capability have dealer or aftermarket support for trailer harnesses that simply plug in to the vehicle’s factory wiring harness. Early Broncos do not. However the factory Bronco harness has the advantage of simplicity of design. After examining the taillight harness it became clear that a plug-in trailer harness would be a piece of cake to build.

The stock Bronco taillight harness runs down the driver’s side frame rail toward the rear bumper. Just above the rear spring hanger is a harness connector that supplies running lights, brake/turn lights, and backup lights to the rear. This is a 4-pin flat connector just like those used for light duty trailer applications. There is also a taillight grounding bolt within 6” of the connector. Everything needed for a simple trailer hookup (running/turn/brake lights, and ground) is located right there and the factory harness already uses the most common trailer connector.

Parts List:

I picked up the pigtail and extension at my local Checker Auto parts.

Basically what you’re going to do is plug the 4-pin extension in between the factory connectors with the pigtail attached to the extension. Pretty simple right? Well almost. The only part that requires thought is the color code of the wires and their attachment to the extension. Ford used its own color code in the Bronco harness and standard 4-pin trailer connectors use almost the exact color code.

So far so good. Now for a couple problems. The standard 4-pin has a particular pin order in the connectors and the Bronco harness uses a different pin order. The 4-pin has a ground wire in the connector and the Bronco harness doesn’t, it has the backup wire instead. These problems are easily remedied when the pigtail is connected to the extension. When connecting the pigtail you need to match its wire colors/functions with the Bronco colors/functions, not the extension’s. In other words disregard the extension’s wire colors because they’re not in the same order as the Bronco harness order. For the ground wire in the pigtail you will just attach it directly to the Bronco ground point.

On the extension separate the wires.

Label the wires with the Bronco wire order.

Near the mid point cut the white, brown, and yellow extension wires. Leave the green wire intact.

Split the pigtail wires approximately 11” down. Cut the yellow, green, and brown wires so as to leave the white wire about 10” longer than the other 3. Strip the ends of all wires.

Now attach the pigtail colors to the colors you marked on the cut extension wires. You will be joining 3 wires together at each point, both pieces of the cut extension wire and the corresponding pigtail wire. Don’t forget the heat shrink tubing before you solder.

Slide the heat shrink tubing over the joints and heat. Attach a lug terminal to the white wire on the extension.

If you want a professional look add some wire loom.

Unplug the factory connectors and plug the extension in. Attach the ground lug to the ground point and route the pigtail out the back.

That’s all, you’re done. Now you have a trailer harness that requires no modification of the original Bronco harness and you can add or remove it with just one bolt.

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The purpose of this article is to help those who seek to upgrade their alternator to the large housing Motorcraft 1G version. The information covered here will only pertain to the mounting process and will hopefully give an idea of what materials may be needed to help in mounting the alternator to your engine. This information is specifically for the stock V-belt configuration and is not intended for those who choose the serpentine setup common to EFI motors. This Alternator is a tough workhorse, and its low RPM performance is surprising. This charging system performance upgrade will allow the use of the existing voltage regulator and requires minimal wiring modifications. If your Early Bronco has the stock V-8 engine configuration, and is a 1974 or later, there is a good chance that it still has the large cast iron alternator mounting bracket. If so, it will need to be removed in order to easily mount the 1G 100A large housing alternator. If you plan to run the smog pump and or air conditioning, perhaps the following modification is not the best suited for your particular application.

Size comparison:
Here are the 2 Motorcraft alternators that use an external voltage regulator: 1G small, which is factory equipment on the early Bronco, is shown pictured on the right and the 1G large on the left.

Misc. Hardware:
If you need new brackets, you can find some of this stuff at your local favorite wrecking yard. Many of the Bronco parts suppliers that advertise on this site have these brackets available brand new, with chrome plating, as well as good used hardware at fairly reasonable prices.

Upper bracket:
This upper mounting bracket can be found on a wide variety of mid sixties to mid seventies Ford cars and trucks equipped with either 289 or 302 engines. I like the ones that were stock on 1965-67 models because they were stamped from heavier gauge metal. Unfortunately, the thicker brackets are becoming rare and getting harder to find. The OE number found on the part pictured here is C8OE-10156-A, and came factory on a 1969 Ford Econoline with a 302.

Spacers:
These alternator spacers come in many different lengths to serve Ford’s wide variety of applications and engine configurations. It is important to get a spacer with the correct length to insure proper belt alignment. The spacer length we are concerned with is 1.640” long or (1 5/8”) and can either be steel, or aluminum. The aluminum spacers are found on the later than 1967 engines. The extruded aluminum spacer is pictured on the left, notice the split in it lengthwise.

Bolt:
The bolt is a 7/16”-14 size. It’s shank, not counting the head is about 5 ½” long. It is a shouldered bolt that has only 1 1/4” of thread length. Earlier cars used a grade (5). The later years used a grade (8). The grade (8) bolt is stronger and what I recommend especially if your engine is modified for a higher than stock horsepower rating. Install this bolt using a split lock washer.

Lower Bracket:
The stock lower bracket for 73 and earlier Broncos equipped with the V8, is the shorter of the 2 pictured, and sometimes requires elongating of the slotted hole at the far end in order to get the belt tension tight enough. If your alternator has a larger than average pulley, modification of the slotted hole may not be needed. Notice it is more angular than the longer one. The longer lower bracket works better for mounting the large housing alternator. It is curved at the lower end and works very well for getting that extra bit of belt adjustment needed. The OE numbers stamped into these parts are as follows:
Short, C9OE-10145-B
Long, D3UE-10145-AA

Note: These are engineering numbers shown as examples. These numbers can vary slightly from year to year and yet be the same bracket.

Mounting:
Displayed below is a picture of the Large Housing 1G 100A Motorcraft Alternator mounted on a 1973 Bronco with a 302 engine. It is using the stock (shorter) lower bracket. No modification was necessary to the bracket because the pulley used was 2 7/8” diameter. If a smaller pulley is used, it may be best to either elongate the slotted hole with a rat-tail file or invest in the longer bracket. Notice how the upper bracket attaches to the water pump? The lower bracket attaches to the timing chain housing. The location of the spacer is between the alternator housing and the cylinder head. The 5 ½” bolt passes through the upper bracket, then through the alternator mounting boss, then it passes through the spacer before threading into the cylinder head.

After mounting the alternator, check the clearance between the lower radiator hose and the lower alternator mounting bracket. You may need to adjust the hose position so it does not rub against any of the new hardware.

Tech article by Howard Eglett (BwoncoHowie)

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I guess you could call this a Junkyard Tig Welder. The idea is you can mount a regular Ford 130 amp 3G style alternator on to your air compressor (or similar motor) so that you can use the belt drive off of the compressor to turn the alternator. Using a battery jumpstart box to give the field its current, then regulate the current through a headlight dimmer switch. Then hook your Tig torch up to the case of the alternator and run the ground clamp to the output stud.

Basically the motor from the compressor will be able to spin the alternator fast enough (approximately 6000-7000 RPM’s) to generate the necessary power. You will probably have to put a v-style pulley on the alternator for sufficient tension. The green wire on the alternator is connected to the case as is the torch and the negative side of the jumpstart box. The blue wire is the field current, which runs to the dimmer switch so that the current from the jumper box can be varied to the desired output for the alternator, and then it goes to the positive side of the jumpstart box. Then the grounding clamp is connected off of the positive stud on the alternator.

Fortunately alternators are rated for 100% duty cycle so once you get it started (you have to scratch start it) it can keep going. At the full 130 amps you limited to about 3/16 maybe 1/4 inch metal. If you really want to get fancy you can run a wire from the negative side of the jumper box to a micro switch on the handle of the torch and tie it to a relay between the dimmer switch and the battery so that you can stop the arc and continue to hold the torch in place to cool the weld with the shielding gas. Other than that the only other things you would need would be an accessory kit for tig welding and a gas bottle with argon.

I know there are allot of people who like to, or would like to do their own fabrication and the price of a good Tig Welder can run from about 2000 to 5000 dollars which makes it just a little pricey. So, if there was a way to get those results for about 300 dollars I thought I should pass it on. I cannot take credit for this idea but, there a number of people where I got it that said it works great but as with any kind of welding it takes a few times to get the touch. I am currently in the process of collecting all the material to put it personally to the test and hopefully can have some decent results. I am also including some pictures and a simplified diagram.

Tech article by Richard Burris (ricks77eb)

Simplified Drawing without micro switch.

Simplified Drawing with micro switch.

Alternator mounted to compressor for Tig.

Example Weld: 304 stainless schedule 10 pipe weld

Example Weld: Custom made header

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When I bought my Centech harness two years ago, I discovered that they supplied a wiper switch that was completely different than the one in my Bronco. Besides being different, it didn’t interchange mechanically or electrically with the stock switch. It required modifying the hole in the dash, modifying the wiper motor and it didn’t have a connector on the back of the switch- just individual wires with spade connectors. I already had an intermittent wiper switch from a Ford F150 pickup, and I didn’t want to give it up. So I figured out how to modify the new harness to accept my intermittent switch. Since then, I’ve had several requests from others on how to do this modification. Here’s what I learned, and how to do it

1. You will need the stock Ford wiper switch electrical connector from your old harness to do this mod. Cut it off with about 3 inches of wire, to make electrical hookup easier. If you don’t have the connector anymore, you’ll need to get one from a junkyard donor. The following photo shows a picture of an OEM Ford wiper switch connector:

Ford used the same connector on a zillion vehicles from the mid 60’s through the 80’s. In the late 70’s some vehicles (F150’s and Broncos) came with a two-piece connector. I recommend avoiding those. They will work but are clumsy to connect.

2. DO NOT MAKE THE MODIFICATION TO YOUR WIPER MOTOR THAT CENTECH DESCRIBES IN THEIR INSTRUCTIONS! The “Motor Stop” circuit is required in order for the intermittent switch to function.

3. The Centech harness is missing a wire required to use the Ford switch (for the Motor Stop circuit), which you need to add in order for this to work. I just used a length of black 18 gage wire (same color as the Ford wire that Centech eliminated) and routed it along the harness from where the wiper connector is located, over to the rest of the wires going to the wiper motor. I used electrical tape to hold it to the harness. Note that this wire does NOT serve the same function as the black ground wire that’s already in the Centech harness. It’s there in case you are using a fiberglass body, to ground the motor case. DO NOT connect the Centech ground wire to the “Motor Stop” wire.

4. Ford made their wiper switches, and the corresponding electrical harnesses in two flavors. The older ones had seven wires going into the electrical connector. The later ones (after about 1979) had six. However, they all used the same plastic shell for the connector. The late models just an empty slot where the older ones had the seventh wire.

The difference was in how the washer motor was powered. The extra wire came from the fuse panel and was used to supply power for the washer motor function. Ford added a jumper inside the wiper switch on the later models so that the washer circuit could be powered from the same source as the wipers. Simplified things and probably saved a little money.

The intermittent switch assemblies thus also had 6 or 7 wires respectively, depending on the year of the vehicle. The seven wire switches are less common. A six wire switch can be made to work with a seven wire connector (what all early Broncos had). Determine which style you have, then follow the rest of the directions accordingly.

5. Note that even among early Broncos the wire colors changed over the years, I’m not going to refer to any Ford wire colors in the directions below.

6. For reliability, I recommend soldering each connection and applying heat shrink tubing. Much more robust than crimp splices and/or electrical tape.

7. Now the nitty-gritty connection details. The following photo shows a picture of the harness connector, taken of the face that mates with the wiper plug, with each terminal numbered. Use the table appropriate to the intermittent switch you have. Cut the spade connectors off your Centech harness at the wiper switch, then follow the numbering in the table to make the new connections.

IF YOU HAVE A 6-WIRE INTERMITTENT SWITCH:

IF YOU HAVE A 7-WIRE INTERMITTENT SWITCH:

If you do the hookup for a 7 wire intermittent switch and later want to use a 6 wire switch, do this: cut the jumper from terminal 4 to terminal 2. Use a jewelers screwdriver to pop the now-disconnected spade connector out of the terminal 4 hole. Pop the purple wire out of the terminal 3 hole and move it to the terminal 4 hole. The terminal 3 hole remains empty. That’s it, connect the 6 wire intermittent switch- the washer function works the same as the older switches.

8. Now you can make the connections from the Centech harness to your wiper motor, except of course you will ignore their admonition to not make the Motor Stop connection. For the record, I never had the fuse-blowing problem with my wipers as described by Centech, either with my stock wiper switch or with the intermittent switch, when I still had the stock Bronco harness, and still don’t.

Once you have made all the connections, plug in your switch and enjoy having intermittent wipers!
Tech article by Lars Pedersen (Lars)

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The purpose of this article is to help provide a little background information to troubleshoot most basic electrical problems. The information contained is from personal experience in the automotive field and is not to be understood as absolute or the only solution to finding electrical problems. Some of the hints I suggest you will not find in any book and, may not apply to your particular situation. I will assume you have some basic background knowledge but I will try to make my explanations as clear as possible.Diagnosing electrical systems can seem overwhelming, but if you break it down into smaller pieces it will be easier. Many people just go out and replace things until they end up replacing the faulty part. While there are times this is the only way, (substitute a known good part), it is costly and frustrating. Invest your money instead into a Service Manual with a wiring diagram and a quality Volt-Ohm meter.

Basic Tools and Caution:
The most helpful tool you can have is quality high impedance Volt-Ohm meter (low impedance Voltmeters will give misleading information, and can damage sensitive electronics). Two test lights, one the run of the mill test light found in any parts store or tool truck. The second one is homemade from a headlight (fig. 1). I prefer to use the small replaceable ones found in composite headlamp assemblies. Lastly, a couple of good jumper wires with alligator clips on both ends. A quality wiring diagram will speed the diagnosis process tremendously. Whenever making electrical repairs or doing major repair work, ALWAYS DISCONNECT THE BATTERY. Batteries can and do EXPLODE! Avoid creating sparks near the battery by turning all accessories and the key off before undoing the cables. The negative side should be the first undone and the last reconnected. Pay attention to where your test leads are; don’t let them get in the fan while the engine is running.

Consider the electrical system on your vehicle as a collection of many smaller sub-systems capable of working independently of each other. Electrical circuits can be broken down to six (6) simple components. Power source, protection, control, load, ground, and wiring. Power source is considered the battery, protection is the fuse or circuit breaker, control is the switch, load is the component doing the work (lights, starter, coil, etc.), and a good ground. The wiring connects everything together. Remove any one component and the system will not work. Electrical diagnosis is a systematic method of identifying and correcting the problem component. The problems you will find are: open circuit, shorted circuit, excessive resistance, and faulty parts.

Begin your diagnosis with the basics:

• Fully charged battery
• Clean battery terminals
• Inspect positive and negative cables for proper routing and clean tight connections
• Inspect fuses
• Inspect bulbs
• Look for any non-factory wiring (alarms, trailer wiring, stereos).
• With the exception of blown fuses, this will correct a large majority of problems.
• A blown fuse indicates a short curcuit and further investigation is required.

Most electrical diagnosis is done with the battery hooked up and the system operating (for example: you cannot check the turn signals without first turning on the ignition switch and placing the turn signal lever into either the left or right position).

Open Circuits:
Use your test light to make a quick check for continuity. Hook the wire lead of your test light to a known good ground or the negative side of the battery. Quickly test your light by touching the probe end of your test light to the positive side of the battery, if it lights up you are good to go on with testing. Never use your probe to pierce the insulation of a wire. Turn the faulty circuit on and use the probe of your test light to check for voltage at various points. I like to start at the positive side of the “load” first. If the light comes on your circuit is probably* good to that point. Check the ground or negative side of your “load” if the light comes on the “load” is probably** good. The problem most likely lies in the grounding side of your circuit. The quickest test for an open ground is to run a known good ground wire (jumper wire). If your test light did not light up at the positive side of the “load” then back up to the switch controlling the circuit. Your light should come on when you probe the “hot side” positive side of the switch and also on the “cold side” negative side of the switch (switch on). Your light still not coming on? back up to the fuse block. You have located your open circuit between your light on and light off tests along the circuit.

* May still have excessive resistance.
** See appropriate shop manual for further testing of your component.

Excessive Resistance:
A test light is used to check for voltage at a particular spot, continuity. Test lights are handy and very useful but can be misleading at times. A Voltmeter measures voltage potential and if used correctly measures resistance in an operating circuit. (An ohmmeter can only measure resistance of a component out of the circuit.) A Voltmeter is essential but if not used correctly, it can be misleading also. Learning to do a voltage drop test will help you solve the majority of your electrical problems. Some tests are easier if you have a helper.

How to use your Voltmeter to perform a voltage drop test:
See Fig. 2 and 3
Do not disconnect or remove any wiring or component in the circuit you are testing. This test is used to isolate excessive resistance in the wiring leading to and from your load. To check the “hot side” of your circuit hook the positive lead of your Voltmeter to the positive side of your battery. Hook the negative lead of your Voltmeter to the “hot side” of your load. Operate the circuit and read the voltage displayed on your Voltmeter. For high current wires (battery cables) you should read less than 0.2 volts. Allow 0.1volts maximum for every switch or relay contact in the circuit located between your test leads. All other wiring should read less than 0.1 volts (some fuel-injected circuits are less). To check the “cold side” negative side of your circuit, hook the positive lead of your Voltmeter to the negative side of your load and the negative lead of your Voltmeter to the negative side of the battery or a known good ground. Operate the circuit and read the voltage on your meter. Any Voltmeter readings above 0.2 volts while attempting to operate the circuit you are testing indicates excessive resistance. Use your Voltmeter to locate excessive resistance by isolating sections of the circuit between your test leads. Note: If you isolate a broken wire between your test leads and attempt to operate your circuit, your Voltmeter will read battery voltage.

Shorted Circuits:
Short circuits show up as blown fuses, melted fusible links, and burned wiring. Never replace burned fuses with a fuse of a higher rating. Short circuits are easy to identify but not always easy to locate. I use my homemade test light to help locate short circuits. Replace the blown fuse with this test light. The resistance is low enough to allow most circuits to operate normally and still protect the wiring. When the short circuit is present, the light will glow at full intensity. If the short is intermittent the circuit should work normally and the light will not glow at full intensity until short occurs. I have located most intermittent shorts by wiggling the wiring in the suspected circuits. This is where a wiring diagram comes in very handy as some fuses protect more than one circuit. While the test lamp glows at full intensity start disconnecting, one at a time, the different loads in that circuit. When you disconnect the offending load or wiring connector to a wire harness and the test light goes out your short circuit is downline from that point.

Faulty Parts:
By using the methods above with the appropriate repair manual and wiring diagrams you can check all the wiring in your vehicle. These tests will help you determine whether or not your “load” is faulty or if it is the wiring. If you suspect your “load” device is at fault the repair manual should be able to provide you with specific off vehicle testing methods. Some manuals will not give specific testing instructions; instead they will tell you to substitute a “known good part”. By conducting your diagnosis properly you can feel good about buying that expensive, non-returnable electrical part.

Poor grounds:
Poor grounds cause a lot of different problems. Dim lights, slow or no cranking, and poor battery charging are classic indications of poor grounds. Use your Voltmeter to do a voltage drop test to check for poor grounds. Hook the negative lead of your Voltmeter to the negative side of the battery and the positive lead to a good ground location on your engine block and note the voltage while cranking the engine. Check the body ground by moving your positive test lead to the body and turn on all lights and accessories, note the voltage reading. Anything above 0.2 volts indicates excessive resistance in the ground connection or ground cable.

Fig. 1 My homemade test light. 9006 high beam bulb. Caution this bulb can get very hot and it will burn whatever it touches.

Fig. 2 The Voltmeter is set up to test voltage drop on the Pos. battery cable. Arrows point to the proper connection points. The test leads isolate the cable from battery to solenoid. Attempt to crank the engine and note Voltmeter reading.

Fig. 3 The Voltmeter is set up to test voltage drop for the ground side of the starter solenoid. Arrows point to the proper connection points. The test leads isolate the ground circuit for the solenoid. Attempt to crank the engine and note the Voltmeter reading.

Notes:

• The basis of the tests assumes conventional current flow, positive to negative, not electron flow.
• Hot side is defined as the positive battery side of a component.
• Cold side is defined as the negative battery side of a component
• Regular test lamps check continuity.
• My homemade test lamp will test continuity, substitute for most loads on your vehicle, and can be used as a visual reference to locate short circuits while protecting the wiring.

Examples:

The following stories will help explain what I am talking about.

A late model car owner came into the shop with the following complaints.
Speedometer (electric) and gauges were not working. A quick check of the fuses revealed a blown fuse. Replacement of the fuse restored operation and a quick road test confirmed the repair? The vehicle returned the next day, same complaint. Dang now what? Intermittent? The wiring diagrams showed exactly what circuits were protected by that fuse. I replaced the fuse with my homemade test light and drove the car; still the problem didn’t surface. Back to the wiring diagram. The same fuse protected the reverse lights. I blocked the wheels, put it in reverse and turned on all systems associated with that fuse and let it run. In less than two (2) minutes my test light came on at full brightness and all systems quit working. I started my search with the easiest “load” I could get to. To make a long story short I ended up unplugging the reverse light connector in the trunk, VIOLA! my problem went away. One of the reverse bulbs was shorting to ground inside itself when it got hot. After it cooled off everything worked normally until it got hot again. Try to justify diagnosis time to warranty on that one.

One of the shops where I worked had a fuel-injected vehicle that would crank and not start. Quick checks revealed a lack of fuel pressure. The man (not me!) working on it disconnected the connector at the fuel pump and checked for voltage with test light, the light came on. Bad fuel pump right? He replaced the pump. Still would not start, must be a faulty new pump. To be sure he unplugged the pump and checked the voltage going to the pump at the connector. 12 volts, it has to be a bad new pump right? WRONG! Most common test lights require very little current to light up; the Voltmeter showed voltage potential not the ability to carry a current. This fuel pump when operating draws 1-2 amps of current and up to 4 amps to start up. A voltage drop test will measure the resistance in a circuit. A voltage drop test showed 10 volts. Voltmeter connections were made at the + positive side of battery and the “hot side” of the fuel pump connector, fuel pump hooked up, and attempting to run fuel pump. Ten (10) volts were being used between the battery and the fuel pump. A check of the wiring diagram showed power from the battery going through the fuse, fuel pump relay, and two different connectors before reaching the fuel pump connector. A voltage drop test across the fuel pump relay contacts showed less than 0.1 volt. This reading is as expected. A look at the vehicle again to find the two connectors in the wire harness revealed a “green” corroded connection (corroded = high resistance) inside one of the connectors that fed power to the fuel pump. A quick test would have been to install the headlight test light in place of the pump and operate the circuit. A headlight test light draws almost 4 amps of current. The light would not have come on at all because of too much resistance in the circuit. While this test would not have pinpointed the problem it would be a quick check of the circuits ability to carry current and run the fuel pump.

Problem: Cranks slow.Test #1 - Make the following checks first:
Fully charged battery
Clean battery terminals
Inspect Pos. and Neg. cables for proper routing and clean tight connections.

I ignored the above suggestions for this article to show the voltage readings of a bad starting system.

Test #2 – Check the battery. Measure the battery voltage before you start. Pos. lead of Voltmeter to Pos. terminal of battery and the Neg. lead of Voltmeter to Neg. terminal of battery. 12.5 volts or better is good, if less then charge the battery first. Attempt to crank the engine and note battery voltage, 9 volts is minimum. Anything less indicates a poorly charged or bad battery.

Test #3 – Check the ground system. This test checks the integrity of the entire ground system from the battery to the engine block. Leave your Neg. Voltmeter lead hooded to the Neg. battery terminal and move the Pos. lead of Voltmeter to a clean ground on the engine. Attempt to crank the engine and note the battery voltage. Any reading above 0.2 volts while cranking is bad. My reading was 1.09 volts.

Test #4 – Check the Pos. side. This test checks the integrity of the entire Pos. side of the starting system between the battery and the starter. Remove your test leads and hook the Pos. Voltmeter lead to the Pos. battery terminal and hook the Neg. Voltmeter lead to the starter motor terminal. (Cable from solenoid to starter.) Attempt to crank the engine and note the Voltmeter readings (ignore Voltmeter reading before cranking). Any reading above 0.3 volts is bad. My reading was 3.48 volts.

Test #5 – Check the starter cable. Remove Pos. Voltmeter lead from battery and hook it to the starter side of the solenoid and note Voltmeter reading while attempting to crank the engine. Any reading above 0.2 volts is bad. My reading was 2.43 volts.

Test #6 – Check the solenoid contacts. Hook your Voltmeter Pos. lead to the battery terminal side of the solenoid and the Voltmeter Neg. lead to the starter terminal of the solenoid (ignore Voltmeter reading before cranking) and note Voltmeter reading while attempting to crank the engine. Any reading above 0.1 volt is bad. My reading was 0.07 volts.

Test #7 – Check the battery cable to starter solenoid. Hook Voltmeter Pos. lead to Pos. battery terminal and voltmeter Neg. lead to battery side of solenoid. Attempt to crank the engine and note Voltmeter readings. Any reading above 0.2 volts is bad. My reading was 1.01 volts.

Interpreting the test results:

• Test #1 will solve many starting problems.
• Test #2 will test the basic integrity of your battery.
• Test #3 Ground system. Result of test indicates a poor ground condition. Visual inspection revealed loose and corroded battery cable to terminal connections. Block connection was good. The proper repair will be a new Negative battery cable. See Fig. 1
• Test #4 Positive side. Result of test indicates poor connections (too much resistance).
• Test #5 Starter cable. Result of this test indicates a poor connection or cable. Visual inspection confirmed a bad cable, melted insulation at terminal connector for solenoid. This cable needs replacing. See Fig. 2
• Test #6 Solenoid contacts. This test indicated good solenoid contacts. No problem here.
• Test #7 Battery cable. This test indicated poor connections. Visual inspection confirmed dirty connection between battery terminal and cable.

Make the needed corrections indicated by the tests above and retest the system to confirm the repairs you made were effective. If it still cranks slowly, the starter motor is bad.Problem: Engine does not crank, solenoid chatters or doesn’t click

1. Complete test #1 and #2 above.

2. Check ignition switch. This is a quick test of the circuit between the battery and the solenoid. Remove the wire going to the solenoid “S” terminal and hook up your headlight test light. One lead to the wire removed from the solenoid the other lead hooked to a known good ground. Attempt to crank the engine and observe the test light. If the light comes “on” at full intensity, this circuit is good. If the light does not come “on” or does not come “on” at full intensity, further testing of this circuit is required. The tests for this system are beyond the scope of this text. Consult your wiring diagram and perform the voltage drop test on the components in your system (key switch, neutral safety switch, and wiring).

3. Check the solenoid ground. This test assumes your ignition switch circuit is good. Use your Voltmeter to perform a voltage drop test to confirm the ground. Hook the Neg. lead of Voltmeter to Neg. terminal of the battery and the Pos. lead of Voltmeter to the ground lug or bolt of the solenoid. Attempt to crank engine and note the volt reading on your Voltmeter. Less than 0.2 volts, good reading, no problem with ground. More than 0.2 volts indicates a poor ground to the solenoid. No reading would indicate a possible open circuit in the solenoid itself. Substitute a known good solenoid or remove the solenoid and test as per your Repair guide. There should be a resistance value in your Repair guide for the “S” terminal to ground. A 0 (zero) ohms reading would indicate a shorted winding and an (infinity reading) would indicate an open winding. Any other reading should be compared against the specs in your Repair guide. If the results of your tests confirm the solenoid is good, verify the ground cable between the battery and engine block to make sure it is good. If the solenoid tests good and the ground cable is good, then the starter motor is bad.

Fig 1 Note corrosion on cable and under terminal. Arrow points to loose bolts.

Fig 2 Arrow points to bad cable. Note insulation has overheated and peeled away. Wire is corroded inside cable terminal end.

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They’re bulbous, ugly, protruding pieces. They look out of place, like they don’t fit, as if they were some designer’s afterthought. They’re often cracked, broken, or missing. Their gaskets are usually cracked, petrified, shrunken shadows of their original selves – offering no protection from the elements and certainly not adding any visual appeal to the grille to which they’re mounted.

Before...

...and after.

We’re of course talking about the turn signal/park lamp lenses and gaskets installed on all 1969-1977 Broncos. The 1966-68 models were dressed with small, clear lenses inset into the grille. They look right. The grille was designed for them. Their flush mounting adds a certain sleekness missing from the later models. For 1969, faced with changing lighting regulations requiring orange lens, Ford engineers designed a modification to the original turn signal socket that allowed the larger orange lens to be added to the grille. In 1970, they went one step further and added side marker lights to meet the new federal lighting requirements now in place.

Thom Cheney is no stranger to most Bronco enthusiasts. In addition to being the premier artist in the Bronco community, he is also a member of that terrific triumvirate that puts on SOB at Sand Lake, Oregon, every year. And in recent years, his endeavors have included building a beautiful uncut Bronco he lovingly calls “Alice”. Like many Bronco owners, Thom has steadily been performing Alice’s transformation from an ugly duckling into a beautiful swan. And of course, the transformation has included the retrofitting of the 1966-68 turn signal lenses into Alice’s later model grille.

The conversion is an easy one, and costs about the same as buying a new set of 69-77 turn signal/park lamp gaskets. The orange lenses used in this conversion were originally sourced for an early ’60s large Ford car. In true Ford fashion, they work on a variety of vehicles. I bought my parts from Wild Horses, but other Bronco vendors sell the same parts. Follow along as we add just a bit of beauty to the grille of a 1969 Bronco.

Parts List:

• 1 set of 66-68 amber turn signal lens $11.98 pr. (WH P/N 9342)
• 1 set of 66-68 front signal lens gaskets $4.00 pr. (WH P/N 9344)
• 4- #8-32 x 1″ screws $2.00 (approx.)*
• 4- #8-32 nyloc nuts $1.00 (approx.)*

· Note: Stainless hardware is a nice touch in this application. Hex cap head screws (aka “allen head” screws) work very well and are visually appealing.
· My total cost for this conversion (including several wheels for my cut-off tool) was about $20.

Tools required:

• Screwdriver
• Drill & assortment of small drill bits
• Pliers
• Marker
• Cut-off tool (Dremel or similar type tool works very well)
• File/belt sander
• Allen wrench assortment

Procedure:
1. Remove the old lens and gasket from the parking lamp assembly. Discard.

2. Remove the lens from the parking lamp assembly so it’s not damaged during the modification process.

Figure 1

3. Unplug the parking lamp assembly from the wiring harness. Detach the assembly from the grille and remove. Once the parking lamp assembly is removed, you can easily see the pieces that were added to the grille for the later model lenses. (See Figure 1) You’ll want to mark the top and bottom pieces for cutting and removal. The following photo shows where to cut along the bottom.

Figure 2

4. And this photo (Figure 2) shows the piece after removal from the truck. This photo gives you a good idea what must be cut to remove this piece from the truck.

Figure 3

5. Once the lens bracketry is removed, the opening your grille should have two small tabs remaining. One is shown in figure 3 above.

Figure 4

6. Using a pair of pliers, carefully bend these two tabs so they extend into the hole opening as shown in the photo below (do not drill the holes yet). Figure 4

7. Now that the grille opening has been modified, it’s time to modify the light housing itself. The Bronco vendors sell the 66-68 light housings by themselves for $40 each, but since we’re typical Bronco owners (i.e. cheap), we’ll modify our existing light housings and save the $80 for something else.

Figure 5

8. Take your 66-68 lens and hold it over the 69-newer housing and trace around it using an ink marker, as shown in Figure 5.

Figure 6

9. Using your small cut-off tool, carefully trim the excess from the housing. This is an interative process. It’s recommended that you cut the housing a little larger than the opening at first and then trim to fit. You want as much “meat” as possible on the sides of the housing because you’ll be drilling through that portion when you mount the housings. When you’re done, the housing should look something like Figure 6 above.

10. Now comes the tricky part. There isn’t a lot of overlap between the ends of your modified light housing and the tabs on the grille. Carefully fit the housing into the grille opening and determine the optimum locations to drill the holes such that they go through both the housing and the tabs. I recommend using a center punch and a small pilot bit in the housings and the tabs to make sure you get the holes where you want them before drilling the final mounting holes. Once you’ve drilled your final holes (3/16″ diameter), test fit the hardware to ensure everything fits correctly.

11. Now that everything fits, you’re just about done! Reinstall the lens into the park lamp assembly and install the assembly into the grille. The lens gasket can be a bit cantankerous – I like to use a little silicone or gasket adhesive to hold it in place. Then place your new lens on and install the screws and locknuts. Tighten up the hardware after making sure the gasket is centered correctly and plug the lamp back into the main harness.

12. Repeat the process for the other lamp and then enjoy the new look of your grille.

Final product.

Special thanks to Thom Cheney for showing me this modification and inspiring me to finally do it to my own truck.

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