How To Install Curt 7-way Connector C55774 On 2002 GMC Sierra Where OEM Connector Was Cut Off

Question:

I purchased the Curt C55774 wiring harness for my 2002 GMC Sierra 1500 I recently bought that has the factory tow package. What I didnt realize is the previous owner cut the factory plug off to wire in a 4 flat harness. Do you sell the factory end I can splice into the truck wiring or can you tell me which wires go together if I cut the round adapter off the Curt harness I bought from you?

asked by: Forrest F

Helpful Expert Reply:

We have just what you are looking for!

Since the factory connector on your 2002 GMC Sierra 1500 was cut off by the previous owner, you can add a new one using the Tow Ready Replacement 7-Way Harness and Socket for Factory Tow Package # 20147. This will give you the correct connector to plug into the Curt T-Connector Vehicle Wiring Harness for Factory Tow Package - 7-Way and 4-Pole Flat Connectors # C55774 you purchased.

Now to install the # 20147 you will need to use a circuit tester # PTW2993 to test the function of each of the cut wires on your Sierra and match the functions to the functions of the harness which are as follows:

Black wire is 12v power
White wire is ground
Red wire is left turn signal
Blue wire is brake output wire
Green wire is tail lights
Yellow wire is reverse lights
Brown wire is right turn

I included videos of the products mentioned for you to take a look at.