Gen 1 light stays on

[SugaPop]

I’ve read a few posts about the GEN1 light, and have checked off the following. Alternator has tested good, and wires are checked (all seems good). Is there anything else I’m missing on why the lights pile stay on?

 

[Evil Dr. Porkchop]

I had the same problem with an alternator some years back. The light was always on but other than that it worked normally. The problem was in the alternator itself as it did the same thing in multiple trucks.

 

[Barrman]

I hate to assume. But, are you by chance talking about a CUCV?

If so, how did you check the alternator?

Did you load test the batteries and are they fully charged?

 

[SugaPop]

I hate to assume. But, are you by chance talking about a CUCV?

If so, how did you check the alternator?

Did you load test the batteries and are they fully charged?

Took the drivers side alternator to get rebuilt and they tested it prior to the rebuild and told me it was good. I’m gonna put it back on tonight. I had both batteries tested, one was bad and I replaced it. Once I’ll put the other battery on a charger to see if that works.

 

[SugaPop]

I had the same problem with an alternator some years back. The light was always on but other than that it worked normally. The problem was in the alternator itself as it did the same thing in multiple trucks.

If charging the one battery doesn’t work I think I’ll swap with the Gen 2 to see if the Gen2 light stays on.

 

[Evil Dr. Porkchop]

If charging the one battery doesn’t work I think I’ll swap with the Gen 2 to see if the Gen2 light stays on.

That’s a good way to check it as long as it’s the original style isolated ground alternator.

 

[SugaPop]

That’s a good way to check it as long as it’s the original style isolated ground alternator.

So I reinstalled the alt. And charged the batteries. The light is very dim now in idle, gets a little brighter in idle with the lights on, and lights up bright as I’m driving.

 

[Barrman]

I had one doing what you now describe. Check your isolated ground wire to the intake manifold at both ends. That fixed one.

Another truck years ago had the same issue. Voltage was good running and I just lived with it. Until it started flickering brightly when I hit big bumps. The positive lead on the back of the alternator was just a hair loose. I wiggled it and got sparks. I put on a different alternator and all is well with not even a dim glow with all items on from the Alt light.

 

[SugaPop]

Thanks Everyone, it turns out the Gen1 regulator was bad, It was overcharging. I installed a new alt. That I found on Amazon and the problem went away.