Bizarre Problem with Left Trailer Turn Signal

Recently got a new 2019 Tundra and I love it, but I’m having a really strange issue with the left turn signal on my travel trailer. To be fair, I can’t quite remember if the issue started before I got the Tundra or after. So what happens when I plug in the trailer lights and have the left turn signal on the truck going is one of three things:

1. The left turn signals on the truck and the trailer work fine.
2. The left turn signal on the trucks works, but the trailer turn signal does not.
3. The left turn signal on the trailer does not work and the left turn signal on the truck stops working. If I turn the turn signal off for a few seconds and then back on the truck turn signal will work again and sometimes the trailer turn signal will start working as well.

Usually wiggling the trailer connector doesn’t seem to affect the working or not working on the turn signal. It’s just when I unplug and replug it that it changes.

 

Be sure to check the ground connector on the trailer side of the harness. Make sure you have continuity from the ground at the end of the cable that plugs into the truck, to everywhere else on the trailer. When the ground on the harness is broken it has to try to ground the trailer through the ball which isn't consistent.

Every single bizarre problem I see with trailer lights has turned out to be a ground problem.

Good luck.

 

Thanks for the tip, I'll check it out. I was testing it yesterday with the truck next the trailer but not on the ball...

 

^^^ This! I have an old dump trailer that has the same issue. Just have to triple check the wires and back up and pull forward a couple of times to make sure contact is good. Eventually I will get to rewiring it

 

did you ever find a fix for this, I have the same issue