Generator light came on

[Spike Jones]

An interesting thing happened last week. I was driving my '58 cab, with approx. 240 miles after reviving it from a 26 year slumber, when the generator light came on. I had polarized the generator when I got it running a few months ago. It had been normal up to that point.

Today, I re-polarized the generator and put everything back together. I then got in the car, started the engine and the generator light went out!! It stayed out even at idle speeds. So I drove it around for about 30 minutes with no change in the light. I turned on the radio, turned on the headlights...no change. I haven't done any voltage tests on the generator yet.
It had been sitting for about 2 weeks.
Any thoughts as to why it might have lost the residual charge??

Thanks
Spike

[Wes Bender]

After you turned off the engine, did you turn the key back on and check the bulb to see if it had burned out?

[Geoff Fleming]

You should have the black box regulator. Remove the cover, (engine off), and inspect the three 'fingers' at the top of the unit. Sometimes they stick after long periods of inactivity and will make the gen. light come alive. Give each finger a gentle tap or two.
I would run a quick field check of the generator...loosen the neg. battery cable. Now, with the engine held at about 2,500 rpm, remove the cable from the battery. The engine should continue to run if the gen. is in good shape. If the engine dies, the gen. should be suspected.
Of course, since you did polarize the gen. and the light went out, things are probably good to go.

[Spike Jones]

Wes...… the light stayed on until I turned off the engine. Then, after turning the key on and starting the engine, the light stayed on.
Now, after polarizing the generator, it comes on when I turn on the key without starting the engine and goes off when I start the engine.

Geoff... I plan to run the voltage test tomorrow.


Thanks for the input.


Spike

[Thomas Sottile]

Make sure the brushes are contacting and are in good shape

[Mike Horton]

Good question, Thomas, but when I helped Spike go through the engine, we did find a weak brush spring, and replaced it, along with the brushes.

[Wes Bender]

If it seems to be OK now, you've verified the gen light is working, it was probably gremlins and I'd just drive it. If you have access to a voltmeter, you could check the generator's output voltage at idle and again at about 1500 rpm or so. That would tell you if you need to chase it further/farther (which one Vic?).

If the voltage is low or it happens again, you'll need to go deeper into troubleshooting mode.

[Jon Schmid]

It's "further," Wes. Their you go.

[Craig Richter]

Jon's smart. "Farther" refers to distance.