1972 GMC Sierra c2500, electric

[Captain J]

Originally Posted by RichardJ

The 4 Amp fuse should be connected to the Junction block at the battery. The wire goes through the firewall connector, directly to the Ammeter. A second wire from the Ammeter comes back out to the other 4 Amp fuse.

You could have a short anywhere on those wires or something shorting the back of the Ammeter.

Excellent illustration, my ammeter works now without this wire, which means previous owner wired it differently,
Should I rewire it back, as you indicated above, or just leave it?
Note: I just bought this car.
Thanks

[Captain J]

Originally Posted by VetteVet

Common sense tells me that a bad battery would start a vehicle good when it was cold, and then not start it when it was warmed up good , rather just the opposite. Heat soak is a common problem with headers or a manifold too close to the starter.

If the solenoid will not click then it is heat soaked, and if it clicks but the starter will not turn, then the starter windings are heat soaked. When electrical items get too hot then the wires will build up too much resistance for the voltage to overcome, and no current flows to operate the items.

If the solenoid is the culprit then here is a very good work around.
Get yourself a Ford solenoid and run the purple GM solenoid wire to it and run the battery positive cable as shown with a jumper from the large terminal on the GM solenoid to the S terminal where the purple wire was originally. The result is you get a full 12 volts to the GM solenoid and it will solve the heat soak issue in most cases. If the starter windings are heat soaked then a heat shield is the best cure less buying a brand new heavy duty starter.

Attachment 1714175

Another benefit of the Ford solenoid is that it takes much less current to activate it, which is easier on the ignition switch for longer life.

Thanks truly for your reply and illustration,
What I did is
I cleaned all solenoid connections/terminals, I cleaned the starter,
I replaced the old Pink and Yellow wires with new wires,
I replaced the battery with new one,
The solenoid and starter work fine,
I just need to test it again by driving and see.
Thanks