Originally Posted by jwharrison
I have a jayco 5th wheel trailer 15 years old the running lights do not work I have voltage for them at the truck. I used two alligator clip jumper wires to be able to check voltage from the truck to the cord on the camper the minute I plug the aligator clips into the camper cord I have no voltage. What would cause the voltage to go to 0 when I plug the cord into the truck.
On my similarly aged Jayco 5th wheel the turn signals started behaving strangely. Signal left, both sides would flash, signal right neither would flash, etc. After getting filthy checking back the trailer's wiring through years of accumulated road grime, I began to think that the fault simply could NOT be in wiring that had never been disturbed. My neighbour suggested that I replace the too complicated turn signal module on my GMC Sierra tow vehicle. He was right; everything has been working properly ever since.