Installing a 4-Way to 5-Way Flat Adapter on a 2011 GMC Terrain

Updated 03/01/2016 | Published 02/28/2016

Products Featured in This Question

Curt T-Connector Vehicle Wiring Harness with 5-Pole Flat Trailer Connector

(36)

$33.64

Tow Ready 4 Pole to 5 Pole Trailer Wiring Adapter

(262)

$17.30

Hook Probe Circuit Tester

(62)

$13.33

Question:

I have a 2012 GMC Terrain with a factory installed trailer package that has a 4 flat connector. My new boat trailer has surge brakes and I need to convert to a 5 flat connector. I looked to splice into the backup lights but they are located in the hatch so a direct connection does not appear to be an option. Any suggestions?

asked by: Richard

Expert Reply:

Even though the actual reverse lights are located in the rear hatch of your 2011 GMC Terrain there could still be a wire that carries a reverse light signal behind one of the taillights. To find it you will need a circuit tester such as # PTW2993 to test the wires behind a taillight while someone sits in the vehicle and puts in in reverse (with their foot on the brake, emergency brake on, and the wheels chocked. Safety first!).

If you cannot locate a reverse light wire this way, then open the rear hatch and look for a wiring harness at the top of the hatch that goes into the roof of the vehicle. You will need to test the wires there too but there will be a reverse light wire there.

After you have located a reverse light wire you can use 4-Way to 5-Way adapter # 20036.

expert reply by: Michael H