cucv charging system m1009

[camobob]

problem is gen 2 lite is dimly on,both batts. are good, both alts. are putting out, front batt. is charging, back batt. is not whats going on?

 

[91W350]

One alternator for each battery. You undoubtedly have an alternator with issues. I had one that had fits for awhile, then the triode quit and there was no charge. Glen

 

[Barrman]

There are numerous threads about checking the alternators on the CUCV's. Just about all that can be written about them, has. Reading the troubleshooting section of the -20 manual will also tell you how to go about checking things out.

 

[Crash_AF]

Pull the small two wire plugs off of each alternator and clean them up. Also pull off the ground wire and clean its connector as well. Gen 2 is the back battery's alternator, so it's not working.

If cleaning the connections doesn't fix it, then you're going to have to rebuild or replace the alternator.

Later,
Joe

 

[Cucvkev]

I'm having problems with my 85 m1009. Put 2 brand new 6tl batts on it rebuilt both alternators. And I'm still having charging issues. What could be the problem?

 

[Rustyshackelford]

Make sure both gen lights turn on before you start the truck.

 

[LastFbody]

I've had a similar thing with mine since day 1. The Gen 2 light has a constant dim glow. The voltmeter reads in the low/mid green, and the truck always starts like a champ. Only weird hiccup is after not running for awhile the voltmeter will fluctuate between yellow and green 5-6 times with the clicking of some relay under the dash. After that it levels out in the low/mid green and everything seems to work just fine.

Im guessing (hoping) just the diode trio. Any of the more knowlegable users encounter my specific symptoms?

 

[dougco1]

I've had a similar thing with mine since day 1. The Gen 2 light has a constant dim glow. The voltmeter reads in the low/mid green, and the truck always starts like a champ. Only weird hiccup is after not running for awhile the voltmeter will fluctuate between yellow and green 5-6 times with the clicking of some relay under the dash. After that it levels out in the low/mid green and everything seems to work just fine.

Im guessing (hoping) just the diode trio. Any of the more knowlegable users encounter my specific symptoms?

Your truck is acting as designed. When cold the glow plugs cycle for a short period, that's why you get fluctuation in the meter, Anywhere in the green is fine but red or yellow? you may have problems.

 

[LastFbody]

So the truck is designed to have a faint glow on Gen 2 when everything is working properly? The glow plug thing accounts for the relay click and the voltage drop at least.

 

[doghead]

No it is not designed to lightly glow.

Typically the voltage regulator is going bad when this happens(if everything else is correct).

 

[dougco1]

Thanks doghead, I missed the faint glow part.

 

[LastFbody]

Thanks for that info doghead, I'll take a poke at that.

 

[HeisenBob]

No it is not designed to lightly glow.

Typically the voltage regulator is going bad when this happens(if everything else is correct).

I know this is an old thread but I wanted to get some clarity for myself. Mine is doing the exact same thing except the slight glow is on the Gen 1 light and my voltage drops to yellow after about 5 seconds and then back to green. It cycled like this for about 30 minutes while driving and then stopped when I got to my destination. Is my issue also the voltage regulator?

 

[dougco1]

I know this is an old thread but I wanted to get some clarity for myself. Mine is doing the exact same thing except the slight glow is on the Gen 1 light and my voltage drops to yellow after about 5 seconds and then back to green. It cycled like this for about 30 minutes while driving and then stopped when I got to my destination. Is my issue also the voltage regulator?

You may have a glow plug temperature sensor that's going bad and it's telling the glow plugs to cycle. When the engine is cold the glow plugs cycle for a short period "30-60 seconds" after start up. That's why you may get fluctuation in the meter. If the temperature sensor went bad it will keep cycling the glow plugs thinking the engine is still cold.

 

[HeisenBob]

You may have a glow plug temperature sensor that's going bad and it's telling the glow plugs to cycle. When the engine is cold the glow plugs cycle for a short period "30-60 seconds" after start up. That's why you may get fluctuation in the meter. If the temperature sensor went bad it will keep cycling the glow plugs thinking the engine is still cold.

Thanks for the reply. I probably should get the volt meter out and test everything following the guide in the sticky. Thanks.