Troubleshooting Tekonsha Voyager Brake Controller 39510 Installation in 2006 Toyota Sienna  

Question:

Expert Reply:

Your Voyager trailer brake controller # 39510 installation should have no effect at all on the functioning of the vehicle or trailer lights since the trailer brake power is carried on its own separate circuit. The only connection the brake controller has to the vehicle lighting is at the brake light switch above the pedal; this connects to the Voyager's RED wire to tell it you are stepping on the brake. Once the Voyager knows you are stepping on the brake its internal circuitry determines how much braking force to send through the blue output wire to the trailer.

What I suspect is that your Sienna's 7-way trailer connector has a corrosion issue or a bad ground. Since you have tested the trailer on its own and everything works its pretty much a sure thing the problem is on the vehicle.

The 7-way socket itself could be the problem or the wiring harness that plugs into the back of it could have corrosion. What can happen is that corrosion in the connector or harness can cause two different circuits to become bridged together. Inspect the socket and the harness that plugs into it for signs of corrosive build-up and clean or replace the fault connector.

The other likely possibility is that the main ground connection for the Sienna's trailer wiring harness is bad. Find where the ground wire for the trailer harness attaches to the Sienna's frame. Remove the ground ring terminal, sand off that spot to expose clean bare metal and apply dielectric grease # 11755 to the grounding point before re-attaching the ground ring terminal. Often providing a strong clean new ground connection can correct many wiring issues. You can also check the ground and power connections for the Voyager to ensure they are solid; these are the white and black wires, respectively.

If you have a circuit tester like # PTW2992 you can test the Sienna's trailer connector for proper function on each circuit without the trailer connected. Have a helper sit in the van and activate each function one at a time while you apply the tester to the appropriate contact. Please refer to the linked photo showing a 7-way socket and the function assignment for each pin. If you do not detect the correct signals on the 7-way contacts then you will know to focus your troubleshooting on that specific van wiring circuit.

expert reply by: Adam R

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