Alternator charging issue

[85SmokinDetroit]

Making a new thread because I haven’t seen a similar issue posted, So I’ve replaced the alternators, relays, printed GM circuit, sockets & bulbs. Gen 1 WILL come on only when I touch a test light to it, (not loose, you can push and pry & nothing) take the test light away it goes off, GEN 2 is just entirely dead in the water. Why? Absolutely zero idea. It worked when GEN 1 took a dump on my way home, with the truck sitting it just entirely stopped working no voltage at the light whatsoever. If you know more than I do please reply, not a very great with wiring, thanks!

 

[cucvrus]

I had a CUCV M1028 plow truck that constantly had idiot light issues and that lead to charging issues. I fixed it a hundred times. I took it to a business that deals in automotive electrical issues and installed self-exciting voltage regulators and that made the idiot light obsolete. It has been working great ever since. The stock 24 voltmeter tells the tale while you are plowing. It charges all the time now. I suspect you have a bad printed circuit board on the back of the cluster. Good Luck. Enjoy the 4th of July holiday.

 

[Mrgior31513]

I agree with Cucvrus, sounds like your ecu's voltage regulator isn't working, unless there is a short somewhere. An external voltage regulator is a simple solution for both issues.

Alternatively, you could look for single wire 24v alternators to replace it with. I had to purchase an external voltage regulator kit for my current engine swap kit, but I only went that route because the alternator is still good and it was still cheaper than replacing the alternator. If the donor engine didn't have an alternator, I would have just bought a single wire one.

It's really not that bad to wire voltage regulators in, but if you are that disinclined to jump into wiring: it simplifies your electrical system even further for added cost.

 

[85SmokinDetroit]

I agree with Cucvrus, sounds like your ecu's voltage regulator isn't working, unless there is a short somewhere. An external voltage regulator is a simple solution for both issues.

Alternatively, you could look for single wire 24v alternators to replace it with. I had to purchase an external voltage regulator kit for my current engine swap kit, but I only went that route because the alternator is still good and it was still cheaper than replacing the alternator. If the donor engine didn't have an alternator, I would have just bought a single wire one.

It's really not that bad to wire voltage regulators in, but if you are that disinclined to jump into wiring: it simplifies your electrical system even further for added cost.

Any shot you could send me a link to purchase the external voltage regulators I’d need to put in place of the dummy lights that’s will self excite, or how would a single wire alternator work on these trucks? You would just leave the other half of the charging system untouched? If you could send me links or explain a little further I would appricate it! Thanks.

 

[85SmokinDetroit]

I had a CUCV M1028 plow truck that constantly had idiot light issues and that lead to charging issues. I fixed it a hundred times. I took it to a business that deals in automotive electrical issues and installed self-exciting voltage regulators and that made the idiot light obsolete. It has been working great ever since. The stock 24 voltmeter tells the tale while you are plowing. It charges all the time now. I suspect you have a bad printed circuit board on the back of the cluster. Good Luck. Enjoy the 4th of July holiday.

I replaced the GM printed circuit board everything around it is new. Issue goes further than that.

 

[Mrgior31513]

Any shot you could send me a link to purchase the external voltage regulators I’d need to put in place of the dummy lights that’s will self excite, or how would a single wire alternator work on these trucks? You would just leave the other half of the charging system untouched? If you could send me links or explain a little further I would appricate it! Thanks.

Actually, looking at your specific alternator: they do have internal regulators, but they are not self-exciting. Non self-exciting alternators require power from the ignition switch to turn on the alternator. One wire alternators are self-exciting and remove that. Installing self-exciting alternators would remove the issue. If you want to find the problem with it, I would guess that you have a short somewhere in the wiring that activates your charging system.

One simple way to see if this is the case is to make a jumper between the Terminal 1 and Terminal 2 to your battery. If you fire up your truck and no voltage, but can get voltage from your alternators by connecting the jumpers, then your problem is in the wiring from your ignition to your alternator.

 

[Mrgior31513]

Any shot you could send me a link to purchase the external voltage regulators I’d need to put in place of the dummy lights that’s will self excite, or how would a single wire alternator work on these trucks? You would just leave the other half of the charging system untouched? If you could send me links or explain a little further I would appricate it! Thanks.

CUCV Delco Remy Starter and Battery Charging Generator

. CUCV Chevrolet's Delco Remy Starter and Battery Charging Generator

www.steelsoldiers.com

The last one is the information for your charging system.

 

[Barrman]

Lets tackle the alternators separately.

ALT 1 on the drivers side has an isolated ground wire but doesn’t need it since it is for the 12 volt truck system side of the fun. If you can touch a test light to it and it works while the test light is touching the case. Then I suggest checking the isolated ground wire to the intake manifold.

ALT 2 on the passenger side has to be isolated ground to the back battery. If it worked before ALT 1 broke but now doesn’t when it wasn’t messed with. Did you unbolt all the battery leads when you swapped out ALT 1? Have you removed and cleaned all the lugs on the firewall above the heater core? If that is done and ALT 2 still doesn’t work then all wires go to the through the firewall plug on the driver side. I suggest pulling that plug out and verifying each pin in the plug goes to where it is supposed to on the alternators and engine. Use the wiring diagram in the appendixes do the -20 TM if you want. But, I think all of the wires in that plug stay the same color end to end under hood.

Stop replacing parts until you check out some more of the basic stuff.

 

[ballencd]

I had a lightning issue from the minute I bought my CUCV. No lights were working. Inadvertently left the headlight switch on and the lights came on at about 0500 in the morning. I played with it some and they started working again and I had no trouble for a few months while I was working on the fuel and injection system but all my lights quit again while I was on the road. It always started and ran. I started troubleshooting and found this....


Got a replacement:

reinstalled with some dielectric grease:

My headlights now work again and are much brighter as are the running and blinker lights.

I would check that first.

 

[85SmokinDetroit]

Actually, looking at your specific alternator: they do have internal regulators, but they are not self-exciting. Non self-exciting alternators require power from the ignition switch to turn on the alternator. One wire alternators are self-exciting and remove that. Installing self-exciting alternators would remove the issue. If you want to find the problem with it, I would guess that you have a short somewhere in the wiring that activates your charging system.

One simple way to see if this is the case is to make a jumper between the Terminal 1 and Terminal 2 to your battery. If you fire up your truck and no voltage, but can get voltage from your alternators by connecting the jumpers, then your problem is in the wiring from your ignition to your alternator.

Thanks for sharing your knowledge, I’ve decided to just buy two One Wire style alternators, being it’ll be as simple as removing the trucks existing excitor circuit, & hooking the rest up the same from what I could tell. It will also allow me to get rid of the momentary lights all together (I’d rather do this, & install a different gauge cluster all together) appricate your comment because I’ve never once thought about self exciting alternators! lol.

 

[Mrgior31513]

Thanks for sharing your knowledge, I’ve decided to just buy two One Wire style alternators, being it’ll be as simple as removing the trucks existing excitor circuit, & hooking the rest up the same from what I could tell. It will also allow me to get rid of the momentary lights all together (I’d rather do this, & install a different gauge cluster all together) appricate your comment because I’ve never once thought about self exciting alternators! lol.

I got that one from my coworker years ago, I'll pass on the appreciation. I agree with him that it really is an odd way to go as far as most charging systems currently function. With smaller vehicles that can be push started from a dead battery: the voltage necessary to initiate your charging system is kind of bleh for off-road/camping life. You're always one shorted battery away from potential severe issues. All you really need is a voltmeter to show you what you're at as a 'dummy' gauge. It's more accurate than a dummy light at showing you what's going on, and I always install one anyways.

 

[85SmokinDetroit]

I got that one from my coworker years ago, I'll pass on the appreciation. I agree with him that it really is an odd way to go as far as most charging systems currently function. With smaller vehicles that can be push started from a dead battery: the voltage necessary to initiate your charging system is kind of bleh for off-road/camping life. You're always one shorted battery away from potential severe issues. All you really need is a voltmeter to show you what you're at as a 'dummy' gauge. It's more accurate than a dummy light at showing you what's going on, and I always install one anyways.

Have to agree a non self exciting alt justt isn’t as great in my opinion, I feel like you’re adding a lot of unnecessary components to the charging system when it could be simplified a lot. In my experience working on these simple is better. The only thing that’s given me issues with this truck is the transmission (due to the hx40 super 64mm turbo bolted to it) & the charging system. Thanks again.

 

[Tow4]

Check your alternators and make sure they are working. Follow this test procedure, Alternator test on the vehicle.

If they are working in the test, you can buy a self-exciting regulator instead of buying the whole alternator. The regulator you are looking for is a WAI D10SE12. These are simple alternators and are easy to work on. There is a link in my signature below to my alternator rebuild thread.