2002 Ford F250, No Trailer Turn Signals

This 2002 Ford F250 came in with the complaint that the turn signals did not work at the trailer pigtail connector. The turns signals on the truck worked okay. Well after examining a wiring diagram I found that fuse number 6 in the interior fuse box supplies power to the right and left, trailer tow relays. I checked the fuse and it was good.

I then checked for power at the relays on terminal #3 which is supplied by the interior fuse #6. No power, must have a broken wire somewhere.

I dropped the interior fuse box so that I could access the wiring behind it. Checking for power on the dark green/orange wire I found that there was power present.

I went back to the relay box under the hood. I released the clip that held it down and removed the rear cover so that I could get to the wiring. Again I confirmed no power was present.

I tried wiggling the wires to see if power would come back but no such luck. I then started tracing the wiring and found that the wires went back to a series of junction connectors at the driver’s inner fender panel. Further inspection found that the wire had been rubbing on a hose and had corroded in (the light green spot) half.


I opened the harness cut out the faulty wire and added a new piece. Another one done.

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