Troubleshooting 7-way Trailer Connector on 2008 Toyota Tundra w/ No Power on Turn Signal Circuits

Question:

We have An 08 Toyota Tundra with factory hitch. We went to hook it up to a trailer and the running lights worked, but the hazards and signals would not. We tried on another trailer and it did the same thing. We are trying to locate the factory converter box but cannot. What could be problem?

asked by: Sam B

Expert Reply:

Good job trying the second trailer, that really helps diagnose things. Since your Tundra has the factory tow package, the turn signals are converted through the tow package. The likely cause of what occurred is a short circuit somewhere in the trailer wiring or the trailer connector on the vehicle that caused one or more fuses to blow.

According to the owner's manual, the following fuses are involved with the tow package. In the fuse box located in the engine compartment, 30 amp use in location 6, a 30 amp in location 13, and a 15 amp in location 15. In the fuse box under the dash, check the 15 amp in location 53.

If you located a blown fuse, replace it but before plugging the trailer back in, you'll need to trace the circuits fed by the yellow and green wires looking for the short circuit. The short could also be caused by corrosion in the connector on the trailer or the one on the vehicle as well, by you'l want to locate the short and repair it, otherwise you'll continue blowing fuses.

expert reply by: Mike L

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Roy H.

3/19/2024

I have no power to my 08 Tundra Stop and Turn Signal on my 6 way plug. All the fuses are good. Connections are good. Any ideas?

Mike L.

3/19/2024

@RoyH I'd recommend using a circuit tester like # PTW2993 on the wiring feeding your 7-way trailer connector. You should see signal on two of those wires with the turn signal activated. If you don't get power and the fuses are okay, there's a wiring problem between the fuse box and the trailer connector and you'd need to have a mechanic look at it. If you DO get power on those wires but not at the pins on the 7-way, the trailer connector is faulty ad should be replaced with # HM11143395.