Now that I have driven my new-to-me 40 GMC a few times now, it seems that the charging system is not working. I'm getting no postive charge at the ampmeter, but when I turn the lights on it shows discharge. Also a small discharge when its running.
I only have a 1939 GMC shop manual, not a 1940. I read the electrical chapter and it shows and discusses a regulator with 4 terminals - "Ignition", "batt", "Gen" and "F". I went and looked at mine and it only has 3 - "batt", "Gen" and "F". It doesn't look like any wires are cut off. I read somewhere that in 1940 they went to a larger generator, could that include a different 3 terminal regulator?
So I'm a bit baffled about how to proceede with troubleshooting. I think I can still ground the field output to see if the gen. is working - right? Is there a good clear wiring diagram online somewhere for a 3 terminal regulator?
I know, I need to get a '40 manual, its on my list.
This is a Canadian built 1 ton pickup with the stock 6v, negative ground system.
I'd appreciate any advice.
Steve
