A note of encouragement to those suffering with wirning goblins. Thanks to 1996 Bronco/F-Series Workshop Manual I FINALLY found the
broken wire that was keeping the RV plug running light circuit dead.
Took quite some time but the pinpoint test did the job. The wire was broken inside the insulation just on the harness side where the 7 pin connector plugs into the main wiring harness.

Typical of an old truck, there was a rats nest of wires that just HAD to be removed. Now I have just the factory harness (+ 1 repair) and a 7 way connector. Less one 6 pin and one 4 way flat and at least one truck length of wire. #14 orange extension cord no less.

So if you are battling the wires, get cozy with that link , grab your multi meter and some test leads and ask some questions. YOU CAN FIX IT!!!!!!

 

Congrats on the fix and thanks for the link.

 

WTG! I know that feeling of licken a wire problem! I agree, GOOD wire diagram and multimeter and a little time and anyone can chase it down. I just like to add 1 thing. RESIST the temptation of putting a probe end on the grinder to jam it in to a good wire looking for power/ground. It WILL corrode out.
Again congrats on the fix!