Loss of Electrical Power

[kvolland]

I have a 1979 F250 4WD. I recently drove the truck with no issues and after shutting it off and going to restart I got the clicking sound most common to a dead battery. I took the battery and had it checked and charged and everything was ok. Because I had a spare starter relay I swapped it out. Then deciding there was a starter issue I pulled and replaced it after it tested bad. None of this has helped. Fusible link tests good. I have no power at all to normal functions, dash lights and guages, headlights etc. I am at a loss. I am guessing a ground issue, but have not been able to trace the issue. Any thougts would be appreciated.

[Bullitt390]

Check the main wiring harness plug located about where the solenoid is. Should contain a thick Black/Yellow wire which is the main power wire.

Josh

[Nathan Plemons]

Originally Posted by Bullitt390

Check the main wiring harness plug located about where the solenoid is. Should contain a thick Black/Yellow wire which is the main power wire.

Josh

Agreed! The front portion of my wiring harness was butchered up pretty bad on my truck when I first bought it. I bought a much cleaner one from a forum member here and installed it. Everything worked fine until I tried to start the truck. I got one click and then pretty much complete electrical failure, not even the headlights worked. To help me figure it out I turned on the lights and started plugging and unplugging until the lights came on. Turns out it was the same plug that Bullitt is talking about. I took some pliers and carefully tightened up the female ends of the terminals on both ends. I actually did that for all of the plugs and coated them all up with dielectric grease and haven't had a problem since.

Sounds like you've got a circuit that is just barely making contact. It makes up enough to power a small load but when you throw the starter current across it, it's opening up. Electrical gremlins, gotta love 'em!