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Gentlemen; I tried to start my M-38 with a 12 volt system today and found that the battery was dead. Apparently either the generator or voltage regulator is not working properly. The battery is new, so that's not the problem. I notice that when I put the headlights on, the voltage meter on the dash moves into the positive side of the gauge. Now, I also noticed that when I blow the horn with the headlights on it sounds very weak, but when I shut the headlights off the horn sounds loudly? Does anyone have any suggestions on what to do? Should I have the generator re-built?

Thanks in advance for your suggestions,
Dennis/New Jersey

Could be the generator or the regulator.

Short answer: take both to a shop that can test both: large trucks run 24 V and should be able to test them.

Thanks Ryan. That is what I will do after the fourth of July holiday/parades.

You said you have a 12 volt system. Do you have a generator or an alternator? What specific model unit do you have?

Hello Wes:

I have a 12 volt Delco Generator with a 12 volt Delco mechanical regulator. I only started using the headlights lately and that is when I started having battery problems. When I restored the jeep, I cleaned and re-painted the generator but never tested it. I did polarize it when I put it back though! I did notice that when I put the headlights on, the voltage meter on the dash goes into the positive side by about 12 volts. I also did noticed that when the headlights are on, the horn sound is very low, then sounds loud after I shut the headlights off.

What do you think is wrong, generator, voltage regulator or both?

Awaiting your expert opinion.

Regards Dennis