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Cant figure out why it keeps DYING!

zerostar2410

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May 19, 2009
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ok, So i just got the bronco running about a month ago and its died 2x while driving.

The first time it died i figured it was a battery issue. Went to costco and got a warranty exchange batter and it ran for about a week with minimal use.

2nd time it died AAA told me it was a bad alternator after they checked it. I replaced alternator and got another battery. It again ran for about a week with minimal use with trips to store and back home.

Today as i was driving home from the store the bronco just turned off while i was driving. I pulled off the road and attempted to start again and got nothing but rapid clicks. Called AAA and they gave me a jump and i drove it home only for it to die in the driveway as i watched the volts slowly go down on my optishift controller.

can anybody offer any guidance or help? I have a mustang 5.0 with explorer serp, volvo fan and relays, and 4r70w with optishift controller.
 

Rustytruck

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get a volt meter and check the battery, start the bronco and while running check the battery voltage again. then turn all lights and accessory's you have and check the voltage again. A charged battery should be close to 12.7 volts. a charged battery while running will be over 13 volts. a battery under charge due to electrical usage should be closer to 14 volts. I am assuming that with a serpentine drive you would be running a 3 g alternator conversion. Make sure there is power on the red and green wire on the alternator with the key on and running. no power there the alternator wont charge. You can always take the battery wire off and pull the alternator and have it tested at the auto parts. You also need to know if someone swapped in what is called one wire alternator. They work slightly different.

https://bcbroncos.com/wp-content/uploads/3g_a17a8148-07ef-4fdd-b4e4-2b60394389cd-1.pdf
 

DirtDonk

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...The first time it died i figured it was a battery issue. Went to costco and got a warranty exchange batter and it ran for about a week with minimal use.

FYI, remember in the future that if your engine dies while it's running, it's normally NOT a battery issue directly. Even if your battery completely dies while the engine is running (or even if you completely disconnect it and remove it from the vehicle) your engine will continue to run off the alternator.
That's how it works normally anyway. The battery is just storage to start the engine, or run accessories while the engine is off. Once the engine starts, your charging system runs the entire vehicle.
So your old battery may very well have been dead, but that was not what stopped the engine from running. And if the battery was still good, it died because the alternator was not able to keep it charged.

2nd time it died AAA told me it was a bad alternator after they checked it. I replaced alternator and got another battery. It again ran for about a week with minimal use with trips to store and back home.

Just like the first time. This is because, with minimal use, a good battery will keep things working apparently just fine, until it can't anymore.
Perfect example of the charging system not working.

You attempted to fix that with the new alternator, but it sounds like it did not actually fix it.
Like Rusty said, you will need to check other things in the wiring.
You could also have gotten a bad alternator right out of the box. Unfortunately this is all too common these days, so don't rule it out.
New no longer means it's good.

Today as i was driving home from the store the bronco just turned off while i was driving. I pulled off the road and attempted to start again and got nothing but rapid clicks. Called AAA and they gave me a jump and i drove it home only for it to die in the driveway as i watched the volts slowly go down on my optishift controller.

Same scenario all three times. This last time however, you did not have a new battery that was fully charged. Only the charge that was put on it by AAA so it was not enough to stay running.
You have an Optishift? What has the voltage been reading all this time? Before it dies? Before it was slowly going down this time? What are the numbers?
As said, if you're not seeing 14.5 almost all the time at least, something is wrong. Anything less than 13v while running is just going to slowly drain the battery. If less than 12.5v then the charging system is doing literally nothing.

Like suggested, measure voltage at the Green w/red wire with the key ON. Should be 12v or close to battery voltage.
Is your White w/black wire connected to the small terminal on the side of the alternator?
Is your Yellow (or Yellow w/white maybe?) wire connected directly to the battery? Either through the main charging cable/stud at the back of the alternator, or somewhere along the line to the battery positive side.

Got pics? Maybe we can see something obvious.
Did you happen to have them test the new alternator? You might have to.
Did you by any chance paint or coat the Explorer brackets? You might have to clean the contact points so that the alternator case can ground to the engine.
What about the main charge cable? Does it have a fuse? Have you checked the fuse to see if it's not blown? Measure voltage on both sides of the fuse.
That's about it for now. Let us know what the volt readings were and are, and where things are connected and we can go from there.

Good luck.

Paul
 
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zerostar2410

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get a volt meter and check the battery, start the bronco and while running check the battery voltage again. then turn all lights and accessory's you have and check the voltage again. A charged battery should be close to 12.7 volts. a charged battery while running will be over 13 volts. a battery under charge due to electrical usage should be closer to 14 volts. I am assuming that with a serpentine drive you would be running a 3 g alternator conversion. Make sure there is power on the red and green wire on the alternator with the key on and running. no power there the alternator wont charge. You can always take the battery wire off and pull the alternator and have it tested at the auto parts. You also need to know if someone swapped in what is called one wire alternator. They work slightly different.

https://bcbroncos.com/wp-content/uploads/3g_a17a8148-07ef-4fdd-b4e4-2b60394389cd-1.pdf


This is the alternator I have, 1996 Ford Explorer. It has a yellow wire and a green/red wire. The yellow wire goes to a 175amp mega fuse and then to the battery. The green/red wire isn’t hooked up to anything. I was told that went to a gauge to monitor volts if I ever wanted to hook one up. By what you’re saying that isn’t true?

Where can I get power for this wire? Why does it need power if the yellow one is already getting power?
 

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DirtDonk

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Yes, the Green wire is the "exciter" wire for the regulator and is the only thing that tells the alternator it's ok to "turn on" and charge.
So it must be connected to switched power.

Still have the original wiring harness? There was a matching Green w/red wire over on the passenger side for the original voltage regulator. You could extend that easy enough.

Paul
 
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zerostar2410

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Yes, the Green wire is the "exciter" wire for the regulator and is the only thing that tells the alternator it's ok to "turn on" and charge.
So it must be connected to switched power.

Still have the original wiring harness? There was a matching Green w/red wire over on the passenger side for the original voltage regulator. You could extend that easy enough.

Paul

The wiring in this thing is kind of botched. A lot of wire nuts, cuts, and splices. I’ll search for it. I think I’ve read that it should be on passenger side inner fender right?

As always, thanks guys!!
 

rjrobin2002

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Always check for voltage increase to around 13 while running before and after a Alt swap. Let's you no its generating and if a alternator is needed.
 

DirtDonk

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Yes, if this is the '72 in your sig, the old regulator would have been just to the rear of the battery and either on the wheel well, or more likely on the inner fender skirt. If it's not there anymore (it's not needed, so might have been tossed) the wiring might be. Look for any unused wiring, especially in a 4-position flat connector with three wires.
If you find that, you'll actually find both the old Green w/red and the old Yellow wires.

In '73 (or if yours is a very late build '72) your regulator and wiring may have been on the firewall right behind the passenger side wheel well.
If your Bronco came with the factory style radiator coolant recovery bottle mounted to the top of the wheel well, your regulator was likely on the firewall.

Paul
 

DirtDonk

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Oh, and there may also have been an anti-dieseling solenoid on the old carburetor. So you may have a Blue, or Blue w/black, or Gray wire between the firewall and engine back there that would also be on with the key.
The danger of using any wire but the Green w/red wire is that it might be on with the key in ACC. That's not good, because if you're listening to the radio for awhile, you could drain the battery because the alternator is pulling power too.

Paul
 
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zerostar2410

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My system never read anything higher than 12V. It always read 11.1-11.3 until it was about to die and then would gradually lower and shortly die.

Found the flat connector and blue solenoid. Can I just cut both flat and circular plugs off? There’s no other end to them. Once I cut do I just connect both green ones?

What’s the yellow wires for?
 

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gr8scott

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That "solenoid" is the noise suppressor for the radio. The green wire is the one you want. I would just cut it and leave everything
else intact.
 

DirtDonk

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My system never read anything higher than 12V. It always read 11.1-11.3 until it was about to die and then would gradually lower and shortly die.

Well now you know what to watch for. If you see voltages that low while the engine is running, you know something's wrong.

Found the flat connector and blue solenoid.

Looks like it's near the rear corner, near the firewall? Seems yours would be a late '72 then. Any chance your VIN has a "P" or "Q" in the sixth position? If so, have you been over to Viperwolf's "P's and Q's" thread to post up your info?

Can I just cut both flat and circular plugs off? There’s no other end to them. Once I cut do I just connect both green ones?

As Scott mentioned, for now I would leave the other ones intact and just cut the green one for now. Attach it to the green wire at the alternator and you should be golden.

What’s the yellow wires for?

Same thing the Yellow wire on your new alternator is for. The long one coming out of the harness is the "sensing" wire for lack of a better term. It's the one that tells the voltage regulator how much voltage there is in the overall system, as seen near the battery. If it's showing a low voltage, the regulator senses this and tells the alternator to put out more to keep the battery topped off.
So obviously not only is it important, but it's important to keep it reading as near to true battery voltage as possible.
For now the Yellow wire by the firewall isn't doing anything. Nor is it needed, because you have the new Yellow wire with the new alternator.

The second Yellow wire is simply attached to a capacitor/condenser to reduce radio noise especially on AM. There was usually one on the positive side of the ignition coil as well.

Paul
 
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zerostar2410

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My VIN number has a P in the 6th location. Haven’t seen viperswolfs post on P’s and Q’s but I’ll be sure to search for it.

I recently hooked up the check engine light so I could see issues arising. Why didn’t the check engine light turn on when it realized the exciter wasn’t hooked up or that there was a potential issue?

I could have sworn someone told me to hook up an LED light inline to that green wire to notify me that the alternator is working. Is that something that needs to be done or even possible?

The only gauge on my stock cluster that doesn’t work is the amperage. How do I get that to work with this alternator? If not possible, how would I hook up an aftermarket gauge or should I just continue to rely on my optishift controller for that info? I just hate having to toggle back and forth between the menus in the small controller.
 

DirtDonk

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My VIN number has a P in the 6th location. Haven’t seen viperswolfs post on P’s and Q’s but I’ll be sure to search for it.

Cool! Another one to add to the list. Here's the link:
http://classicbroncos.com/forums/showthread.php?t=221155

I recently hooked up the check engine light so I could see issues arising. Why didn’t the check engine light turn on when it realized the exciter wasn’t hooked up or that there was a potential issue?

Not sure, but I bet it has to do with the age of the computer, and it not being all that smart compared to a more modern OBDII version.

I could have sworn someone told me to hook up an LED light inline to that green wire to notify me that the alternator is working. Is that something that needs to be done or even possible?

Might be the same guy that told you that the Green wire was for a volt gauge.
And I meant to say before that they were not completely wrong about that.
In a "normal" vehicle, you have your battery indicator light on the dash. This light is actually in-line with the Green w/red exciter wire. It does double duty then, by starting the alternator when you turn the key on, AND showing you when your generator/alternator is not working.

In a vehicle like ours with an ammeter though, it was expected back then that everybody watched the gauges now and then, and knew how to interpret when the ammeter showed a discharge when it shouldn't. So Ford left the green wire indicator light out of the equation and simply ran the green wire directly to the regulator. Simplifies things a tiny bit.
A side note to this is how the two different setups are wired in old Fords. You've seen the 4-wire connector with only three positions used. The corresponding letters are: F S A and I. Where F is for "Field" and S is for "Stator" and A is for "Armature" and I is for "Indicator" (as in, the dash light).
For ours, I use the words F for "Field" (as normally used), A for "Always" (as in always powered) and I for "Ignition" (as in switched).

The lamp circuit, when used, is a pretty clever little guy. The Green w/red wire has 12v with the key, but if the light bulb ever burned out the power would stop and the alternator would turn back off.
So they run a bypass circuit around the bulb in the dash, use a resistor to make the path through the bulb the easier path. But if the bulb burns out, the power keeps flowing around the bulb and keeps the alternator charging.
When the alternator is not charging, the bulb is illuminated from the power coming from the ignition switch. When the alternator is charging, the circuit is equalized (or whatever the proper electrical term is?) so current does not flow in either direction more than the other, keeping the bulb from illuminating.
Works really well.

The only gauge on my stock cluster that doesn’t work is the amperage. How do I get that to work with this alternator? If not possible, how would I hook up an aftermarket gauge or should I just continue to rely on my optishift controller for that info? I just hate having to toggle back and forth between the menus in the small controller.

Yeah, since you need that big heavy battery cable sized wire for charging the battery now, it's too big to run through the dash and the ammeter (which takes direct readings off of the old charge wire). So unfortunately we lose the ammeter with more modern alternators.
You can replace that ammeter with a stock-looking volt-meter though. Something like these that we sell: Bronco Voltmeter that goes into the stock location.

Simple hookup to any voltage source. Typically to the input side of the old IVR (instrument voltage regulator) on the back of the cluster, or the stud coming out of the center of the ignition switch. Or even the Green wire that the mechanic was mentioning. It's just that wire is not as simple as the others.

Paul
 
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zerostar2410

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Cool! Another one to add to the list. Here's the link:
http://classicbroncos.com/forums/showthread.php?t=221155



Not sure, but I bet it has to do with the age of the computer, and it not being all that smart compared to a more modern OBDII version.



Might be the same guy that told you that the Green wire was for a volt gauge.
And I meant to say before that they were not completely wrong about that.
In a "normal" vehicle, you have your battery indicator light on the dash. This light is actually in-line with the Green w/red exciter wire. It does double duty then, by starting the alternator when you turn the key on, AND showing you when your generator/alternator is not working.

In a vehicle like ours with an ammeter though, it was expected back then that everybody watched the gauges now and then, and knew how to interpret when the ammeter showed a discharge when it shouldn't. So Ford left the green wire indicator light out of the equation and simply ran the green wire directly to the regulator. Simplifies things a tiny bit.
A side note to this is how the two different setups are wired in old Fords. You've seen the 4-wire connector with only three positions used. The corresponding letters are: F S A and I. Where F is for "Field" and S is for "Stator" and A is for "Armature" and I is for "Indicator" (as in, the dash light).
For ours, I use the words F for "Field" (as normally used), A for "Always" (as in always powered) and I for "Ignition" (as in switched).

The lamp circuit, when used, is a pretty clever little guy. The Green w/red wire has 12v with the key, but if the light bulb ever burned out the power would stop and the alternator would turn back off.
So they run a bypass circuit around the bulb in the dash, use a resistor to make the path through the bulb the easier path. But if the bulb burns out, the power keeps flowing around the bulb and keeps the alternator charging.
When the alternator is not charging, the bulb is illuminated from the power coming from the ignition switch. When the alternator is charging, the circuit is equalized (or whatever the proper electrical term is?) so current does not flow in either direction more than the other, keeping the bulb from illuminating.
Works really well.



Yeah, since you need that big heavy battery cable sized wire for charging the battery now, it's too big to run through the dash and the ammeter (which takes direct readings off of the old charge wire). So unfortunately we lose the ammeter with more modern alternators.
You can replace that ammeter with a stock-looking volt-meter though. Something like these that we sell: Bronco Voltmeter that goes into the stock location.

Simple hookup to any voltage source. Typically to the input side of the old IVR (instrument voltage regulator) on the back of the cluster, or the stud coming out of the center of the ignition switch. Or even the Green wire that the mechanic was mentioning. It's just that wire is not as simple as the others.

Paul


So how would I go about hooking up an indicator light? You said to run it online but does that mean to connect both wires from my LED light to the green/red wire? Or do I still ground one side of the light and the other side to the green/red wire? Looking to put the light on my column bezel.
 

DirtDonk

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If you need the thing charging today, just connect the green wire to the ignition-on source and run around to test it. That way we know everything works before you mess with a custom circuit.

But otherwise, yes, you connect one side of the lamp to the power source (ignition switch) and the other side to the regulator's green w/red wire. Hence the "in-line" designation.
I'm not really sure if you have to do anything odd for an LED vs an old incandescent bulb though, so wait for an electrical expert to chime in with a better description.

The trick to long term success though is to run the "bypass" that I described before.
This allows the alternator to keep charging even if the bulb burns out. Doesn't matter if it's an LED or a regular bulb, once it burns out it no longer passes current through it to reach the alternator to tell it to turn on.
The bypass needs a resistor in it of such a value as to be more resistance than the bulb, but not so much it will lower voltage at the Green wire by any substantial amount. You only want it bypassing if the bulb burns out. Electricity always follows the easiest path, so a little additional resistance is what keeps the light lit when the key is on and the engine not running. Or when the alternator stops working.

Yes, you may have a volt gauge to keep track of that system, but a light sure makes it easier to take notice when it stops charging.

Good luck.

Paul
 

gr8scott

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510 Ohms based on this diagram I got from an old post.
 

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gr8scott

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Something like this:
https://vetco.net/products/510-ohm-...MImJqyhtW-3QIVil9-Ch0oNg08EAQYASABEgKA4PD_BwE
It bypasses the lamp in case it blows, keeping the alternator on so it can keep charging. I think you have to use a
regular bulb as current has to flow through it. Don't think LEDs work that way. But as Paul said, don't worry about a charge light just yet.
Connect those green wires and make sure your alternator is doing what it should.
 

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zerostar2410

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Something like this:
https://vetco.net/products/510-ohm-...MImJqyhtW-3QIVil9-Ch0oNg08EAQYASABEgKA4PD_BwE
It bypasses the lamp in case it blows, keeping the alternator on so it can keep charging. I think you have to use a
regular bulb as current has to flow through it. Don't think LEDs work that way. But as Paul said, don't worry about a charge light just yet.
Connect those green wires and make sure your alternator is doing what it should.

Green wires connected. Everything working and charging. Bronco on and reading at 14.4V.

Now need to get the charging lamp working with the resistor. So each side of the resistor is connected to each side of the lights wiring and into the green wire?
 
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