How to Add 4-Way Connector to 2003 GMC Envoy with an OEM 7-Way

Updated 07/28/2023 | Published 07/27/2023

Products Featured in This Question

Curt T-Connector Vehicle Wiring Harness for Factory Tow Package - 5-Pole Flat Trailer Connector

(55)

$17.19

Curt T-Connector Vehicle Wiring Harness for Factory Tow Package - 4-Pole Flat Trailer Connector

(757)

$40.09

Curt T-Connector Vehicle Wiring Harness for Factory Tow Package - 7-Way and 4-Pole Flat Connectors

(761)

$37.30

Curt No-Drill Bracket for 6-Way or 7-Way Round Trailer Connector Mounting Bracket - Long

(331)

$38.69

Question:

I bought a curt 56515 uscar custom wiring connector, but it doesn fit in my factory port which i took a pic of. It even says Gm on port cover flap

asked by: Jeffrey G

Helpful Expert Reply:

Thank you for the photos!

It looks like you're trying to plug the Curt T-Connector # C56515 directly into the 7-Way blade connection on your 2003 GMC Envoy, when this wiring is actually designed for you to disconnect the current 7-Way connector from that US CAR connection. In the second photo you sent in (from behind the 7-Way) you can see where your OEM plug meets the back of the 7-Way connector - that's where you'll disconnect it.

Since I imagine you're wanting to have the 4-Way connector and the 7-Way connectors readily available I recommend using the Curt T-Connector # C55384 which tees in behind the 7-Way but it actually has an output US CAR on it as well so your OEM 7-Way can plug in.

For an all-in-one system we also have the Curt # C55774 which places both connectors neatly next to each other and can be secured to your trailer hitch with the No-Drill Bracket # C57202.

I've linked some installation videos you can reference for the installation.