I was able to get Ford E350 wiring diagram and a mechanic who assured me that the turn signal line, once energized at the multi function switch on the steering column, the power then runs to the rear light with NO intervening fuses, relays, or other stuff.
THUS -- disconnect the negative lead on the battery. Then, three phillip head screws later, and I have the multi function switch exposed.
Not a big deal but JAYCO runs a pair of wires to the back, and just before they touch the light, they are connected and proceed as a single wire. For me, I cut the Scotch Crimped connector, and isolated the lines, both pairs, four wires, left side and right side. (if you keep the wires mated, the multiMETER gives odd results).
At the turn signal in the cab, the #5 pin drives the right lights. As this was working, I tested continuity on it, first. It showed NO RESISTANCE, meaning the wire was intact from front to rear.
Then, again at the turn signal in the cab, the #9 pin drives the left lights. This was the side that WAS NOT WORKING. THe continuity test showed an OPEN CIRCUIT. This means the wire is broken someplace between the front and rear.
I ran a new wire. Temporarily pinning it into the circuit. YES! Lights work as they are supposed to. So I then cut the old wire near the #9 pin, soldered it in, taped it and put shrink wrap on it as well. Went for a drive with the wife!
THANK YOU.
