The Stovebolt Site Forums The Shop Area The Electrical Bay Sudden loss of everything on startup.

There is only one ground for motor to start. (battery negative cable to motor bolt, you said you cleaned/checked that). If it won't turnover AND no lights. You have a bad battery or a charging system that is not keeping it charged, or both. After battery charged up, check for it to be 12.6V at rest and about 13.5V-14.5V when at high idle. (if it starts). Also a bad battery can show a charge of 12.6V but will fail after a few starts or drives. A load test will show that type of cell failure.

Get a meter that measures volts DC.

Switch from Delcotron externally regulated alternator to Delco 10si. Throw it away with voltage regulator and all that silly wiring.

Also: The other day I saw something that made me think of you. I saw a picture of a GMC instrument cluster that had been fried. As in: shorted out somehow. All of the PC copper runs were black and chipping off. I think that is what you had. I think the black stuff was the protective plastic sheet getting burnt/melted right above the runs and I thought is was a coating on your other post. Now I think it was burn trace. Charred "plastic".