Another tow wiring conundrum
I’ve had a couple posts in the last week, as I solve one electrical mystery, another pops up. Now, when testing my towed vehicle lights, I found a myriad of things that didn’t make sense (e.g. left s...
Forum Discussion
CVD wrote:
Figured a pic might help. I’m at the back bumper of the RV (no toad), have taken apart the tow plug and taped the wires to a piece of wood. With running light switch on, the pic shows current going from the running light wire to ground wire – Expected. However when I touch the running light wire and either of the turn signal wires, I also show current flowing (indicator light on) – Not Expected.
The kicker is if I pull both (left and right) coach turn signal light bulbs (combo dual filament 1157 running & signal light bulbs), then current only flows between ground and running light wires – i.e. fixes the problem (but I would have no back turn signal bulbs)
All of your symptoms still point to an open ground. Either the green wire is such a poor ground it can only power the test light, or it's not even a ground and you'd inadvertently powering something else (brake controller or backup lights?) when you complete the circuit with the green wire.
