A friend recently bought a 71 fleetside shortbed and discovered the taillights, brakelights and rear turn signals don't work. The headlights come on when you pull on the light switch but that is all. We unplugged the light switch and jumpered from the hot terminal (red wire in) to the brown wire and got taillights. We jumpered to the orange wire and got turn signals.

We can't figure out where the problem is. We have proved that the wiring to the rear is good but do not know how the rear lights are powered. The light switch appears to have two circuits (switches) one for the headlights and one for the rear lights. We swapped in a different light switch and had the same problems. We are wondering where the power comes from for the rear lights. We think maybe it comes thru the steering column and turn signal assembly.

We have wiring diagrams but can't make much sense out of them. Any help WILL be much appreciated.

Skidsteer

The schematics are definitely confusing when trying to figure out how switches work. I believe the red wire provides power for the headlights, and the orange wire provides power for the tail lights, turn signals, and brake lights. I'm guessing that you aren't getting any power to the orange wire from the fuse panel. When you put the jumper between the red wire and the orange wire, this artificially put power to the circuits that the orange wire is supposed to feed.

You should be able to measure 12 volts at that orange wire on your headlight switch. You should also be able to measure 12 volts on the orange wire that goes to the brake light switch on your brake pedal assembly.

My guess is that you have a blown "tail stop" fuse. Did you check the fuses?

My friend said all he fuses are good but there definitely is no power to the orange wire. Guess I'll have to check it myself. Thank you for the help. I will post the results.

Make sure you check all the terminals to the fuses, not just the fuses themselves. You may have a rust/corrosion problem with the terminals themselves. That's what happened to my truck. I ended up spending a saturday morning sanding all the terminals and it fixed the problem.