Installing 5-Way Connector on 2005 GMC Envoy  

Question:

Helpful Expert Reply:

If your 2005 GMC Envoy is equipped with the factory US round car connector under the bumper (this is likely what your existing 4-Way is plugged into) the Curt T-Connector Wiring Harness # C56515 you referenced will work perfectly to replace it with a fully-functional 5-Way. The reverse circuit pin will be activated upon installation so that it will power the trailer's reverse signal lights.

If you don't have this plug on the Envoy and your existing 4-Way is installed in another manner then your best option will be to simply add the Tow Ready Adapter # 20036. This will just plug into the current 4-Way to provide a 5-Way at the other end. The additional blue wire you see coming from the harness will need to be spliced into the reverse light circuit wire on the Envoy to activate that pin on the 5-Way.

I have attached a couple short video demonstrations on these products that you can check out as well.

Since it sounds like your trailer also needs some help I recommend using the 5-Pole Flat Connector Harness # A40W5B for re-wiring. This is a wishbone style harness that uses a tail light wiring for each side of the trailer for easier routing and it includes the additional blue reverse circuit wire as well. The harness length is 40 feet.

expert reply by: Chris R

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