WHEN I TURN THE LIGHTS ON THE FUSE FOR THE TAIL ...
1994 FORD F-250
When I turn the lights on the fuse for the tail lights and dashboard illumination blows
Thursday, March 7th, 2013 AT 6:27 PM
First check for trailer harness wires chewed up and shorting together.
A simple trick to finding a short is to replace the blown fuse with a pair of spade terminals, then use small jumper wires to connect them to a 12 volt light bulb. A brake light bulb works well. When the circuit is live and the short is present, the bulb will be full brightness and hot so be sure it's not laying on the carpet or against a plastic door panel. Now you can unplug electrical connectors and move things around to see what makes the short go away. When it does, the bulb will get dim or go out.