Trailer turn signals and brake lights not working.

I have a 2014 Toyota Tacoma with the factory towing package with a 7 pin plug. I rented a Uhaul trailer over the weekend. They used a 4 pin to 7 pin adapter for their trailer. It worked at first but at some point during the day the turn signals and brake lights quite working. When I got home I plugged my travel trailer and got the same results. Running lights and tail lights on the trailer work fine. Turn signals and brake lights don't work. Plugged my travel trailer into our Tahoe all lights work. So it appears it is with the Tacoma. Toyota dealer wants $130 just to diagnose.

Any suggestions?

 

There are three different 30 amp fuses for trailer lights in the fuse box under the hood. Each fuse is in a different group of fuses. Check all three fuses. There is also a trailer light relay. Swap it with the horn relay to make sure it is working.

 

Thank you. I checked the 3 fuses and look to be OK. The relay is hard to remove. Is there a trick to that? I was trying to use a pair of pliers but I was afraid I was going to break the relay.

 

i would swap in fuses you know are good just to be sure. I've had fuses "look" ok that actually were blown.

Does your trailer use the 4 pin adapter plug or was it plugged directly into truck? Could be a bad spot in the 7-4 pin adapter.

 

Thanks for the tip on the fuses. I'll try that as well.

My trailer plugs directly into the truck.

 

Any update same problem, still scratching my head.

 

That was my thought, but tracing it back through the harness all I get is running lights.

 

Last time this happened to me it was the under hood fuses.

 

I'm having a simular situation. Picked up my camper trailer this morning and just after I got on the road my truck started doing all sorts of things. First had no turn signals on the truck or trailer. Then my back up camera would come on and off a few times then noticed my airbag light came on. Got it home and in parking the trailer I noticed it wouldn't come out of park. Had to use the overide switch to finish what I was doing. After disconnecting the trailer, I used my test light and found no bad fuses. Im sure the problem came from the trailer, just not sure how or where to correct the problems with the truck. Then I will search out the trailer issue that caused this. I did disconnect the negitive cable on the battery for about 10 minutes but that didn't solve anything. I will check the fuses in the cab tomorrow, but I don't think those have much to do with the issues I'm experiencing.