Totally stumped w/ charging sys. issue - The 1947 - Present Chevrolet & GMC Truck Message Board Network

newmaac · 12-18-2011, 03:40 PM

Trying to help my son with his 69 C 10 and it's charging issues.
I'll try to keep this brief, but it might not work that way.

We installed a new alternator, (bench tested positive, @ 14.6 volts)
New regulator.

Charging nothing!
The voltage at the battery is about 11, whith the engine running or not.
When the battery is disconnected with the engine running, engine dies immediately.
Voltage @ the red & black terminals on the alt matches what is currently stored in the battery.
All connectors look fine.
The fusable link on the positive from the battery has been eliminated by a PO.
We unwrapped the wire harness and all wires look fine.

I was told that in SOME alternators, there needs to be a small current going INTO the alternator, in order to create the output FROM the alternator. If so, which wire is supposed to bring current to the alt?
Can anyone tell me if we should have current @ the blue or yellow terminals on the alt, before starting the engine? If so, how much?

Any suggestions would be greatly appreciated.
Thanks in advance

Mike, (who hates electrical gremlins)

12-18-2011, 03:40 PM	#1
newmaac Registered User Join Date: Jun 2011 Location: Cupertino, CA Posts: 17	Totally stumped w/ charging sys. issue Trying to help my son with his 69 C 10 and it's charging issues. I'll try to keep this brief, but it might not work that way. We installed a new alternator, (bench tested positive, @ 14.6 volts) New regulator. Charging nothing! The voltage at the battery is about 11, whith the engine running or not. When the battery is disconnected with the engine running, engine dies immediately. Voltage @ the red & black terminals on the alt matches what is currently stored in the battery. All connectors look fine. The fusable link on the positive from the battery has been eliminated by a PO. We unwrapped the wire harness and all wires look fine. I was told that in SOME alternators, there needs to be a small current going INTO the alternator, in order to create the output FROM the alternator. If so, which wire is supposed to bring current to the alt? Can anyone tell me if we should have current @ the blue or yellow terminals on the alt, before starting the engine? If so, how much? Any suggestions would be greatly appreciated. Thanks in advance Mike, (who hates electrical gremlins)



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