Have no turn signal/brake light on drivers side rear. I changed bulbs, still nothing. Have working left turn in the trailer plug.
Can't be a bad ground to the socket (the running lights work). Took my test light and attached from working left turn on
trailer plug directly to turn signal wire on the socket and the test light began flashing.
That tells me the turn signal wire is grounding out somewhere between where the trailer plug splices in and the turn signal socket, correct?

Please help, thanks,
Jay

Sounds legit. But maybe the socket itself is bad, or the bulb is defective. change the bulb with the right side one you know works to at least eliminate that as a prob, if you haven't already done so.

thanks,
I did swap bulbs and they both act the same. I thought about a faulty socket but I have had 2 other faulty sockets on other trucks and when they go bad, nothing works. Never had just one circuit be faulty, might be worth a shot.

Jay

Nobody sells a replacement socket, is this a dealer only item???

Jay