I recently bought a 1986 D250 with the 5.9l 360. Once I got it home, I was further checking some functions on the truck, like the radio and whatnot. I tested the dimmer switch, and immediately my dash lights stopped working, as well as the oil pressure gauge. I was messing around in the engine bay and noticed my oil pressure gauge started working again. Also, when I drop the fuse box, the door buzzer stops buzzing when I move the box around. Any ideas what I could try to solve this? I’m not great at electrical stuff

 

Gotta love electrical gremlins.

Check for loose connections on the sensor, and the fuse block.