Does anyone have a wiring diagram of the fuse box or relays related to the headlights and tail lights? I can run a jumper wire to the lights and they work, but they do not appear to be getting power? Any help please? This is a 1987 D150 ramp pick up.

 

Have a look here. Perusing thru there though, it looks like the headlamps are powered directly thru the dimmer switch... no relays appear to be involved that I can see.

 

The rear lights and parking lights are powered by the "Park/Tail Lamps" fuse in the fuse box located under the dashboard, to the left of the steering column. If the lights work when you jump-start them but don't receive power normally, the problem is often a blown fuse, a faulty headlight switch, or a blown link fuse near the battery.