Adapting 4-Pole Flat on Toyota Sienna to 5-Pole Flat Using Part # 20036

Question:

I purchased and installed wiring harness 118304 for Toyota Sienna. My trailer has surge brakes and needs to connect to reverse light circuit to disable brake when backing up, but this harness does not accomodate 4 wire versus 5. Is there some instruction and parts you can provide to modify my wiring harness to convert from 4 wire flat to 5 wire flat with backup interlock? thanks, dave

asked by: David H

Expert Reply:

To provide the converter you already have with a 5-pole connector, you have two choices. You can use and adapter, like part # 20036. The blue wire on the adapter would tap into the circuit that feeds the reverse lights on your Sienna.

A more permanent solution is available. You can cut off the 4-pole connector on the vehicle, and wire in a 5-way flat vehicle end, part # HM37908. The brown, white, yellow and green wires would match those used by your existing connector. As with the adapter I mentioned above, the blue wire would need to tap into the circuit feeding the reverse lights on your Sienna.

expert reply by: Mike L

Bob

2/8/2013

What specific taillight connector and wire do you connect the surge brake wire to on a 2012 Toyota Sienna?Thanks,

Patrick B.

2/15/2013

We do not have wire information available on that particular vehicle. What you can do is remove one of the tail light assemblies and locate the socket for the reverse light. Note the wire colors and try to locate wiring harnesses underneath the vehicle. Use a circuit tester to verify that the wire only comes on when the vehicle is put into reverse. The other option is to run the wire up to the tail light assembly and splice in there.