Having some lighting issues with my 86 w150. When you turn on the headlights the break light don't work and the tail lights don't come on. It's a 4 speed on when you put it in reverse the tail lights come on but not the back up lights. With the headlights off the brake and turn signals work as normal. Any ideas? Anyone know of an on line wiring diagram? Thanks in advance.

see if www.mymopar.com has it & Google it. EDIT I think I would start at the headlight switch connector

I would check the blinker switch. I was having multiple problems st the same time. Looked at wiring diagram and almost every light on the truck went through the blinker switch. Changed it out and fixed all of the issues.

Mine was an earlier model(1975)so may not be wired the same. Worth checking the schematic.

look under the rear of the bed near the taillight , connectors should be yellow to yellow & black to black on both taillights. Paul

Losing ground back there?

I agree check the grounds at the rear.Remember they ground thru the screws that hold them to the body.Also check under the truck for wires melted by heat.Had that problem on one of mine.Rocky