Wiring Harness
 

How can I test my turn signal switch. I have power and lights to the front of my truck, but have no power or lights to the rear of the truck. Does anyone has a wiring diagram that shows what wire (color ) goes where. I have a 59 F100 and would like to know what wire coming trought the fire wall does what? eg blue to top horn

Google is your friend! :) I realize that the wiring diagram for the v8 is not for a pickup but it still should help.

Buy one of these, they are well worth it. Classic Car Wiring . Com : Home of the original color laminated car wiring diagram

Before doing anything else, run a ground wire from frame to bed. That was what fixed the problem for me when I had same symptoms.