I don't do butt connectors. Solder and heat shrink only.
I did locate the factory harness for the trailer electrical. It was on a cross member directly behind the spare tire. It appears to be a 12-position molex style connector. I verified +12vdc constant on one pin, brake, RH turn and reverse lights. LH turn was either not working or giving milivolts of power rather than +12vdc. I say this because one terminal in the connector gave fluctuating but extremely low voltage when LH turn was on.
I suspect that maybe the factory harness was damaged in some way and rather than fix it properly, the previous owner removed it and then rigged it together using a 4-position trailer harness.
I just looked through my F250 service manual PDF pages that I had copied off the Internet several months ago but apparently I neglected to copy the lighting sections. Can someone here provide me with the pinout for that factory connector near the spare tire position?
Also if we've got a friendly Ford tech or parts manager here, perhaps someone can provide a part number for the harness and 7-position trailer connection that SHOULD be connected to that harness.
Thanks.