Ford Repair: 89 f150 fuel gauge, fuel gauge, f150 4x4

Question
on my 89 f150 4x4 the fuel gauge reads about a 1/4 higher with the tail lights on or when you use the brakes help??

Answer
hey there, This sound like you may have a couple of bare wires touching each other, the harness with the fuel pump wiring and the tail light wiring will run either along side of the frame underneath the truck or  through the truck underneath the carpet, depending on the model of the truck, you are going to have to find this bunch of wiring, trace it back, and carefully inspect the physical condition of all the wiring, find the open and shorted wires, repair and then test it out, i hope this has helped you out.
Chris