Not charging

[StevenJMcTowlie]

91 5 speed 3.1

Okay, here are my symptoms. The other day I was driving and noticed to voltage seemed a bit low sitting around 10 volts. So I pulled into a gas station and shut the car off. Once off the car would not start again. I had a friend come give me a jump, the car started and with the cables hooked up the system was reading 14 volts. As soon as we unhooked the cables my voltage began dropping. I made it a 1/4 mile and the car completely died again. My buddy gave me a push and I was able to pop start it, kept it running for another mile or so and it died again. We towed it home and I brought the battery to the parts store where they said it had a bad cell. Put new battery in and it ran again but still seemed weak.
Today I replaced the alternator(other one was only 2 months old) and belt tensioner and it is still running low voltage. When I turn on the blinkers my tach and other gauges raise and lower with the draw of the signal. The system does not seem to be charging. What besides the alternator could cause the system to fail to charge? I have checked all my wire connections that I can see and they look ok, tight and nothing badly corroded.

After some testing I am thinking maybe the fuseable link between the alternator and starter is shot??

[1990BerettaGTZ2.3L]

Sounds like your internal voltage regulator took a crap ain't hard to change I've done 3 with success tools needed, new regulator of course, sockets to tear alt apart, believe it or not a good strong paper clip to hold the brushes in when putting it back together I recommend drawing a sharpie line on both sides of the alt for when you tear it apart putting it back together with the correct rotation believe me done it on my Chevy truck had to tear it back apart

[Money pit Beretta]

Not sure. Bad ground or something?

[Koots]

Is your battery/low voltage light illuminating when you turn the key ON?

When I was swapping over to the CS130 style alternator on my 83 K5, I learned that the alternator needs a resistance in the L-Circuit (identified on the alternator pigtail) which is commonly provided by the dash light bulb.

So make sure it's not burnt out.

[StevenJMcTowlie]

Is your battery/low voltage light illuminating when you turn the key ON?

When I was swapping over to the CS130 style alternator on my 83 K5, I learned that the alternator needs a resistance in the L-Circuit (identified on the alternator pigtail) which is commonly provided by the dash light bulb.

So make sure it's not burnt out.

Went to advanced auto to have them test the charging system today and they said my alternator is not producing any power at the battery. I pulled the alternator and had it bench tested it it checks out good.
I just went and checked and when I turn the key to the "On" position I dont see any battery light. It makes sense since this started happening right after I swapped in a new cluster with a tach.
Now I can't figure out which bulb would be the battery light, or do I not have one because this cluster has a voltage gauge? Maybe I should just swap my other cluster back in and test again.

edit: After checking the new cluster with a flashlight from behind there is no battery light, just the voltage gauge. When I put the other cluster back in battery light comes on when car comes on and goes away when car starts. Going to drive over the parts store and see if that fixed it. I thought it might have been the main charging wire so I ran a second one in 2 gauge straight to the battery so there is no reason the battery shouldn't see current from alternator

edit2: Just returned from the parts store, with my old cluster back in I am getting 13.6v at idle and 13.5v under load back from the alternator. I can't believe that something like no bulb in a cluster can stop my whole charging system from working.

[Koots]

If you don't have a stock cluster bulb, you can simply wire in a 3w resistor into the L-Circuit and accomplish the same thing. I ended up just wiring in a bulb socket/bulb and covered it up.

[Koots]

Anyway, I'm glad you got it figured out. It's an easy fix and will allow you to keep your new cluster...

I've got to check this out myself, as I've swapped in a full gauge cluster myself recently, but the car is still waiting to be finished.