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Wed Jun 20, 2012 4:33 pm

I have a '63 Beetle that has suddenly started having some sort of electrical issue. The generator light started coming on when I start the car, but would go off for good as soon as the RPMs went above 2000 for a second. As soon as it was back at idle, the light stayed off. Now, a few days later, the light will always stay on at idle. I checked my battery and it's showing about 12.6 volts both at idle and at higher RPMs. I found a topic about re-polarizing the generator by running a jumper between D+ and B+ on the regulator while the car is running. I tried it, and it instantly makes my 'Gen' light go out until the car is shut down, but it comes back on when the car is started again. My generator is a Bosch unit, less than 1 month old. I did the common generator test by running wires from my battery to the generator, and it made it spin with no problems. I swapped out my regulator with a known good one, with no change. The only other thing I can think of is that my battery is shot. It is a few years old, so maybe, but I haven't had any trouble at all starting the car. I'll go swap it out with another one, but I just thought I'd see what other suggestions anyone else has. Thanks for any input!

Wed Jun 20, 2012 5:30 pm

So I swapped out the battery and the problem is still there. The new battery, however, will show around 14 volts at higher RPMs. At idle, when I turn on the headlights, I can watch the voltage drop about 0.01 volts per second. [for example, it will go from 13.50 volts down to 13.40 in ten seconds.] Is that normal? As soon as I turn the lights off, the voltage jumps back up instantly, but then continues to fall. I should have also mentioned, when the generator light is on, it gets brighter relative to the RPMs going up, and it's super bright just before it goes out at close to 2000.

Wed Jun 20, 2012 7:57 pm

Check your generator brushes, and make sure they're not sticking in the brush holders. It sounds as if perhaps they're not seating all the way onto the commutator, which can happen sometimes with new brushes.

With the engine running at idle and the generator light on, take a wooden stick (like a popsicle stick) and push down on the top brush and see if the light goes out. You can do the bottom one too if you want, but one should be enough to tell you.

Wed Jun 20, 2012 8:09 pm

Wow! After all of the tests I ran, pushing on the brushes fixed it. I pushed on the top brush when the problem first started, but this time I did the bottom brush too. It didn't occur to me that they would have trouble seating, but I guess that makes sense. Thanks Donnie for your help!

Wed Jun 20, 2012 8:22 pm

Glad you got it going!