Finding a Reverse Light Wire to Tap Into on a 2014 Hyundai Santa Fe for Trailer with Surge Brakes

Updated 10/07/2014 | Published 10/06/2014

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Question:

I purchased a curt trailer hitch with Hyundai wire harness from you a couple of months back. My trailer has surge brakes and a 7 round plug.I have the correct converter but cant figure out how to connect the surge brake circuit to the car back up light circuit. Dealer wants $200 to connect the back up circuit to the surge brake sensor on the trailer essentially converting a 4 flat on the car to a 7 round. Hyundai has nothing to help. I found the back up light wire in the lift gate. Im a competent hobby mechanic so dont be afraid at being too technical.

asked by: Rich J

Expert Reply:

You will need to add a 4-Way to 7-Way adapter such as # 37185. The 4-Way will plug right into this adapter. Then you will ground the white wire to the frame. The blue wire you will not need since the trailer has a surge coupler. The black wire is for 12-volt power which you may or may not need. And the purple wire is for the reverse lights.

There are a couple of possible places you can find access to the reverse light circuit. It is possible that there is a reverse light wire bundled with the regular taillight wires. You would need to access the backs of the taillights and use a circuit tester like # PTW2992 to determine if there is a reverse light wire.

Otherwise, you will need to find where the wires go from the body of the vehicle into the hatch. You will likely need to cut away some protective covering to access the wires. Then you will use the circuit tester to test the wires until you find the reverse light wire. All of this testing would require a helper to sit in the 2014 Santa Fe with it in reverse and their foot on the brake and the e-brake engaged!

The other possible option is to find the fuse for the reverse lights using the owner's manual. If the reverse lights are the only thing on that fuse, you could use a fuse tap and extra wire to run to the purple wire on the 37185 adapter.

expert reply by: Michael H