Thanks for posting. Sorry to hear this. It appears the problem is upstream from that plug. I suppose you get the same issue with a different trailer module (you said you tried a different one earlier) ?

I really can't offer any more guidance remotely. Most of the time the factory wires/connectors for OEM trailer electronics are completely untouched and work perfectly. I would be looking for any other splices anywhere near the trailer module or rear light wiring. Any tail light error codes on the dash? If, for example, you had trouble with reverse lights, AND you had a back-up camera triggered by the reverse lights, I would be looking at that..But that doesn't seem to be the case here.