• Welcome to ClassicBroncos! - You are currently viewing the forums as a GUEST. To take advantage of all the site features, please take a moment to register. It's fast, simple and absolutely free. So please join our community today!
    If you have problems registering or can't log into your account, please contact Admin.

confused about ignition switch..

Boss Hugg

Contributor
Bronco Guru
Joined
Jun 8, 2010
Messages
2,140
Okay, I'm chasing down what I think to be shorts in my '73, finding that there may or may not be any...

I'm confused over the fact that the ignitions 12v source is about a #14 yellow wire, and the fuse panel is fed from this switch by a #12 bl/g... Why use such a big wire coming out of a switch is the source is such a small wire and feeds other things on top of that? Is there a relay that I can't find?

thanks in advance. BTW, i'm sure this information is here somewhere, but i have one week to make sure my truck is ready to go for some sprint car pushing at the local dirt track, and i have to go finish painting and flooring a nursery for a soon to come baby, so I don't have time to chase this myself.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,275
No relays on Broncos, unfortunately. Except for the starter relay (solenoid) of course, and some horn relays on the later ones.

So, my only thought is that the Yellow wire is so short (spliced into the much larger Black w/yellow or red striped alternator/battery loop) that it didn't need to be a larger gauge. The Black w/green wire however, travels a slightly longer distance to do it's job.
So they saved 8¢ per Bronco. But hey, it added up!
That's just a guess of course, but it makes mass-production sense.

What are your actual problems? I see you have 5 posts now, so did I miss some fun electrical gremlin diagnosis posts already? ;D

Paul
 
OP
OP
Boss Hugg

Boss Hugg

Contributor
Bronco Guru
Joined
Jun 8, 2010
Messages
2,140
Well, lately i've been having trouble determining if the alt is charging the batt or not. i just cranked the rig for the first time friday morning since probably December to get ready for next weekends race. I have a huge halogen light bar that runs 18 amps and some other LEDS on top, and I want to make sure that when I get to the track i'm not gonna run my batt dead in the first few minutes we're there. The reason I'm questioning the charging is that after driving it here and there running errands throughout the day, it gets to the point where the starter won't turn the engine. I have found myself stranded once and I don't want it to happen again, especially when I'm a support vehicle helping a racing show move along. I bought a new starter, but I'm not sure I want to put it on yet, until I know for sure that it's the alt or not. I also went ahead and bought a 130 amp alt off ebay today, and I'll put that on when it gets here later in the week. From what I've read here that should be easy enough.

Right now, my REAL problem is that the bl/y wire feeding the emergency flashers and dome/cigar fuses broke loose from the fuse block. I bought a couple of 6 circuit ATC fuse blocks to replace the old one and be able to add some stuff. I know the big wire off the alt is Bl/y, and that the diagram shows it to split somewhere, and I'm just now seeing that the yellow wire from the ignition switch is in this splice connection wherever it is... So good guessing on the length thing. I think you're absolutely correct, but I don't agree with them doing it that way. I makes me want to wire a relay into it and feed the fuse blocks through that....

BTW, you have responded to both of my last two posts within minutes? Do you get paid to answer these things??;D And I'm not complaining by any means... Thanks for you ideas and help.
 

Steve83

Bronco Guru
Joined
Jul 16, 2003
Messages
8,976
Loc.
Memphis, TN, USA, Earth, Milky Way
Adding relays to take some of the load off the ig.sw. is generally a good idea. Upgrading to newer-style fuses is ALWAYS a good idea. ;)

Two quick workarounds occur to me about your charging problem:
1) Install a cheap voltmeter, even if it's just temporary until you get the new alt installed & working. It'll let you know if you're about to become stranded.
2) When the truck isn't working at the race, hook it up to someone's battery charger at 10-40A.

Here are some revised wiring diagrams that may help:

. . .
 
OP
OP
Boss Hugg

Boss Hugg

Contributor
Bronco Guru
Joined
Jun 8, 2010
Messages
2,140
One last thing before i call it a night... I walked out there to look at something and put my hand on the regulator. It was HOT so i checked the key and it was off... What could cause that???
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,312
One last thing before i call it a night... I walked out there to look at something and put my hand on the regulator. It was HOT so i checked the key and it was off... What could cause that???

A problem. Check for voltage on the green-red wire. Should be zero with ign sw off.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,275
Well, lately i've been having trouble determining if the alt is charging the batt or not.

Easy enough to tell with a cheap volt-meter. Just test the battery terminals when the engine is running and if it's less than 13 volts, you're not getting much of anything at all. Between 13 and 14 and it's charging, but not as much as it should. Between 14 and 14.5 and you're good to go.
edit: As I meant to mention (and Viper reminded me), you need to check the voltages also at both the regulator's Yellow wire, and Green w/red wire.
Yellow should have full battery voltage all the time. Green w/red should have full battery voltage only when the key is on. The level of voltage is important here. If either of those varies from battery voltage by more than a few tenths of a volt, there is something wrong with the wires, the connections, or the switch. They're the sensing wires that allow the regulator to tell the alternator what to do. And if the Green w/red wire is bad, even your new alternator is not going to charge if that's the wire you use to turn it on.


The reason I'm questioning the charging is that after driving it here and there running errands throughout the day, it gets to the point where the starter won't turn the engine.

Sounds like what happens when the alternator doesn't charge, sure enough. With headers and an old starter, you can get that too, but more often that will sound more like a weak starter, then getting no action at all.
When it did this, did you get a click from the relay? Or any movement out of the starter at all?


I bought a new starter, but I'm not sure I want to put it on yet, until I know for sure that it's the alt or not.

Good call. Especially if, when it does start, it sounds just fine.
Starters can do funny things when they get hot, like I mentioned, but it's sounding more and more like your charging system anyway.


I also went ahead and bought a 130 amp alt off ebay today, and I'll put that on when it gets here later in the week. From what I've read here that should be easy enough.

It can be. As long as you bought the right alternator that is. If it's a standard mount 3G from Ford, you should be good to go. Might have to change your old pulley to the new alt, but that's not a big deal either.
But first, I would determine just what the problem is with this one. A non-charging alternator is not always the alternator itself.
Your hot regulator could mean a bad wire somewhere, or a bad regulator (though I'm not sure how it would get hot), or, it could just be the residual heat from when it was running earlier. Here's where you have to check things out with a volt-meter to determine where the fault lies.


Right now, my REAL problem is that the bl/y wire feeding the emergency flashers and dome/cigar fuses broke loose from the fuse block. I bought a couple of 6 circuit ATC fuse blocks to replace the old one and be able to add some stuff.

Yeah, that sounds bad. Like your original fuse panel is rusted enough to have that connection fail. Is it possible that it was just a bad soldered joint? Or is it all pretty rusty under there?


I know the big wire off the alt is Bl/y, and that the diagram shows it to split somewhere, and I'm just now seeing that the yellow wire from the ignition switch is in this splice connection wherever it is... So good guessing on the length thing. I think you're absolutely correct, but I don't agree with them doing it that way. I makes me want to wire a relay into it and feed the fuse blocks through that....

The main push-pin connector is very near the back of the ammeter in the instrument cluster. It's not a bad idea to pull it apart and check it for rust or looseness too. That's a very important junction, as you can imagine.
Funny, but even after all these years, I can't tell you exactly where the splice for the Yellow wire is under the dash. I know where they are in the harness when it's out and laying in the driveway, but have never actually bothered to track it down under the dash. Good luck with that, but it's such a good splice, that there is usually nothing that goes wrong with it. Usually.
If there was ever a serious overload of course, it could damage that splice, but barring that, it should be fine. I'm sure Ford never felt that they were responsible for light-bars, off-road lights, BIG radios, and any number of other electrical things that the future owners might think of using. They just wanted to make it acceptable for the expected work load and that was that. No extra money for anything else.
That's the same logic that led them to feel that a 10 gauge wire was sufficient for the charging wire from the alternator. With a maximum of 45 to 55 amps available for charging on a Bronco, that was literally all that was necessary, and sufficient for their perceived needs. Just like 27" tall tires on 6" wide wheels!
Still, running stuff off of relays to unload that circuit is not a bad idea. Just a bit of work. Just what you were looking forward to I'm sure.


BTW, you have responded to both of my last two posts within minutes? Do you get paid to answer these things??;D

Not yet! Been working on that angle a bit. It's so much fun though, I'd hate to turn it into a job and ruin it.

Good luck. Hope we can help you get this going for your deadline.

Paul
 
OP
OP
Boss Hugg

Boss Hugg

Contributor
Bronco Guru
Joined
Jun 8, 2010
Messages
2,140
Steve: Thanks for the diagrams. I've combined them into one continuous page that prints somewhat well in a "poster print." http://dl.dropbox.com/u/8887252/73-74 bronco wiring diagram.jpg Also, I'm a little weary of adding relays simply because I don't have a lot of experience with them..And it would add to the work load.

Viper: no voltage on gr/r with switch off. BUT..I had not taken enough time to screw this NEW reg onto the fire wall. I just pulled the plug off the old one and stuck in on the new one to test with. Could the heat come from not being grounded?? I think the ground wire is hanging loose off the alt, so.. but especially if it's not grounded it shouldn't conduct electricity...??

This ground wire being loose could cause lack of charging couldn't it? So now which of the two screws off the back should it be stuck on? The high amp wire is still connected.

Also, the wire that has broken off the fuse block is not important from my studying. I'll fix that later with a new harness when the funds allow (just read through most of Erics thread on the build of the new Painless...) along with the steel body kit from Jeff's..

I have worked that connection at the ammeter several times so it should have decent contact..

Basically, if I can get the new reg on the firewall, and the alt hooked up right, it should work. Otherwise, i'm waiting on the new alt from ebay, which I haven't heard anything about since I payed with paypal... :(
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,312
Uh oh. Your new regulator is probably toasted. They are easily damaged if not grounded before connecting power.

With a 130 amp alternator you will need to run the output directly to the starter solenoid or battery or you risk melting more stuff. BC has a good diagram for the 3G.
 
OP
OP
Boss Hugg

Boss Hugg

Contributor
Bronco Guru
Joined
Jun 8, 2010
Messages
2,140
SO looking forward to this new alt and doing away with the regulator. hopefully this thing I paid for is good and will not need to be rebuilt. I could've bought a 130 amp new for about 140 and then add cables, pulleys, tax and core charges from a local guy that used to own the race car I helped on years ago as a high school kid. My heart sank when I heard him quote me that because I knew i could get a rebuilt off ebay for $100 flat...
 
OP
OP
Boss Hugg

Boss Hugg

Contributor
Bronco Guru
Joined
Jun 8, 2010
Messages
2,140
Well guys, I know you're dying to know what's up... I've got a new fuse block installed so all my lights work as they should, the new regulator mounted on the firewall, and an alternator that's charging very well. Looking forward to this weekend!! Now more painting in the baby room....

Thanks for all the help gentlemen!


bronco1.jpg
 
OP
OP
Boss Hugg

Boss Hugg

Contributor
Bronco Guru
Joined
Jun 8, 2010
Messages
2,140
Update!!!

This morning I got in to go somewhere, and the thing acted like it was out of gas, so i turned the key off to go put some in, and suddenly, SMOKE from under the dash in the ign switch area... Hit my power cutoff switch quickly (GET ONE ON YOURS NOW!!!)

Digging into the harness I have found problems...
2013-04-16%2013.45.48.jpg


2013-04-16%2013.45.58.jpg


Then I found the 15A fuse for the cigar lighter popped. Gotta go check for a short there.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,275
Bummer huggins! Question though, is it just the angle of the camera, or do you actually have 11 wires attached to the ignition switch?
Should only be five or six, if I remember?

Paul
 
OP
OP
Boss Hugg

Boss Hugg

Contributor
Bronco Guru
Joined
Jun 8, 2010
Messages
2,140
HAHA, yeah, like 23. needed some juice the new sound system and lights and stuff.

actually, i think the emergency flasher switch was hanging behind it. Think it's only 4 wires. I didn't realize till later that that switch was melted inside, thus hanging down out of position. I've got a lot of problems. After repairing the burned wire (https://dl.dropboxusercontent.com/u/8887252/2013-04-16 17.55.18.jpg), and fixing the loose wire causing the original short, I put power back to it, and after a few minutes of watching, the purple wire off the ign switch (power to prop valve switch and light) started frying. Disconnected it, tried to start the engine, but when I turned the Key to on position, the starter engaged... Probably more wires burned together. yeehaw.

I have a race I'll be working on May 11, and now this...
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,275
Tough one to repair. Looks like you went to a lot of trouble to get it cleaned up.
I worry about the ignition switch carrying all that current for your accessories. It was never designed for that, and it's old too (unless it's been replaced of course) so it could die an early and ugly death.
Or is that what all the relays you're tired of are attached to? It won't have any issues running a few relays I wouldn't think. But it depends on how it's set up ultimately.

Good luck Lot of work.

Paul
 
OP
OP
Boss Hugg

Boss Hugg

Contributor
Bronco Guru
Joined
Jun 8, 2010
Messages
2,140
The switch is only carrying what the factory put on it, nothing extra. I did replace the smaller yellow wire with a heavier one. If I can't chase down the big short that's causing all my problems, I'll wind up doing a quick rewire with Relays, powering only the coil, radio lights, and instr cluster.
 

Steve83

Bronco Guru
Joined
Jul 16, 2003
Messages
8,976
Loc.
Memphis, TN, USA, Earth, Milky Way
There's SOME extra load (possibly on the SWITCHED side of the ig.sw.) that's causing that Y feed wire to overheat. It's not the cigar lighter - that fuse killed whatever overloaded it when it burned out, protecting OTHER wires from turning into heating elements. But whatever you've done at the downstream end of the Y wire is the root cause of the problem. You need to move as many wires as possible OFF the ig.sw. hot post, and put them on new dedicated fuses. If you have a key-switched load, run a small key-switched circuit to a new relay's trigger terminal, and use one of the new constant-hot fuses to power the relay's input terminal. Then send its output to the new switched load. Don't put more than ~20A nominal load on a standard 30A relay. High-quality relay & fuse blocks are common & cheap in JYs, so shop there.

. .
 
OP
OP
Boss Hugg

Boss Hugg

Contributor
Bronco Guru
Joined
Jun 8, 2010
Messages
2,140
I see everything you're saying to do, and I've considered doing that in the past, but... The only thing I have added load-wise is a cd/mp3 stereo head. No amps, no lights (thru the ign switch anyway), nothing. So it's clear to me that I've had/have a short somewhere.

And then add this to the problem, somehow my ign switch got jammed in the start position after I repair that Y feed wire (now pink, it's all i could find that I'd consider big enough). After a few "bumps" to break it free, it broke... luckily i just replaced it last September, so it's still under warranty, and will be replaced after the rain stops today.

Also, the Em Flasher switch is not melted inside (just greasy inside), it just came apart when I started tugging on wires to get them out from under the dash. I will be able to put it back in, saving about 30 bux.

Since i've got the tape cut off the dash harness to look for other bad spots, I'm going to delete some of the unnecessary wiring for emissions and the brake warning light (which has already started to burn). That's just too many problems waiting.

One day I WILL get to my EFI swap which includes the entire 1996 pickup and dash harness (for totally custom dash with p/u steering column), 5.0 w/Expy mani, 4r70W, NP205, and 78 full width 3/4 ton axles.
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,312
I see everything you're saying to do, and I've considered doing that in the past, but... The only thing I have added load-wise is a cd/mp3 stereo head. No amps, no lights (thru the ign switch anyway), nothing. So it's clear to me that I've had/have a short somewhere.

And then add this to the problem, somehow my ign switch got jammed in the start position after I repair that Y feed wire (now pink, it's all i could find that I'd consider big enough). After a few "bumps" to break it free, it broke... luckily i just replaced it last September, so it's still under warranty, and will be replaced after the rain stops today.

Since i've got the tape cut off the dash harness to look for other bad spots, I'm going to delete some of the unnecessary wiring for emissions and such. That's just too many problems waiting.

One day I WILL get to my EFI swap which includes the entire 1996 pickup and dash harness (for totally custom dash with p/u steering column), 5.0 w/Expy mani, 4r70W, NP205, and 78 full width 3/4 ton axles.

1) That yellow is the largest gauge going to the switch. If the path of current was through one of the other, smaller wires I would have expected it to melt before the yellow wire. If it didn't melt any of the smaller wires either the load was shared on more than one of them or the current took a different path to get to ground.

2) There is a ground terminal in the ignition switch. It's used to test the brake warning bulb at startup.

3) Your switch is now broken. Coincidence?
 
Top