Trailer Lights Not Working After Installing Hopkins In-Bed Wiring Harness in 2002 Ford Super Duty

Updated 05/12/2014 | Published 05/11/2014

Question:

I recently installed 40167 Hopkins Wiring for the 2002 F-250 and F-350 Super Duty by Ford, so that I could add a connection in the bed of truck. I plugged the harness into one end of factory harness and the other end into harness that had about 12 inches of wiring that then plugged into back of 7way at bumper. Also in that smaller harness it has 4 wires that appear to be factory spliced into the 7way connection that went to a 4way connector that mounted on a bracket with the 7way. I then mounted the other 7way that came with Hopkins 40167 in bed of truck. I then proceeded to check to see if I had all functions for lights and signals at 7way at bumper and found that I had no tail, brake, or turn signal function in either of the 7ways. I did find a blown 20amp fuse in fuse box at location 6 in fuse box inside truck, but every time I put a new fuse in, it pops. Can you please help me with this problem.

asked by: Jason R

Expert Reply:

The fuse blowing is an indication of a short circuit. Check all of the connections and wiring (as much as you can) and look for any dirt, corrosion, bent pins, or exposed copper strands touching bare metal. Repair as needed, if possible.

It sounds like your 2002 Ford Super Duty came with a factory installed 4-Way that was later converted to a 7-Way. If not all of the wires for the 7-Way at the bumper are ran you will need to complete that but the lighting functions should still work.

If everything was working at the bumper 7-Way before but plugging in the Hopkins harness # 40167 caused it to stop functioning I am inclined to believe there is either a problem with the Hopkins harness or the bumper 7-Way and Hopkins 7-Way are pinned out differently and that caused an overload or short. It would also explain why the lights are not working.

I have included a link to a help article that shows how a vehicle and trailer 7-Way should be configured. Ignore the colors and just go by the functions to determine if the truck 7-Way matches and readjust as needed.

expert reply by: Michael H