How to Wire 7-Way Trailer Connector on 2008 GMC Sierra 3500
Updated 11/09/2017 | Published 11/08/2017
Products Featured in This Question
Question:
I read a wiring description, but I have different wire colors from what was shown. The colors I have are: White, 12 ga. Red, 14 ga. Yellow, 16 ga. Drk blue, 16 ga. Purple, 16 ga. Drk green, 16 ga. Lt green 14 ga. HELP...
asked by: Steve
Helpful Expert Reply:
Wire colors alone are not a reliable method for connecting vehicle or trailer wiring since they are not always consistently used. There are common wire colors for certain functions, such as a brown wire for trailer running lights, but there is no guarantee that this is the wire color used on all trailers or vehicles.
But since you provided the wire gauges too, that does help narrow things down. A heavier-gauge white wire will typically be ground; the other larger-gauge wires will typically be for +12V auxiliary trailer power (likely to be the red wire) and trailer brake power (light green wire).
The best way to go about wiring a 7-way like # PK12-707E is to use a tester like # PTW2992 to confirm the function on each wire. Have a helper activate each light function and apply the tester to each wire while the function is on. This will tell you which wire does what. Then all you need to do is refer to the linked article on wiring to see the function assignments for each of the contacts on a 7-way.
Make sure your main ground connections are secure and made to a clean bare metal surface. Weak grounds can cause all sorts of lighting problems so make sure these are solid. You can apply dielectric grease like # 11755 to help protect those connections from corrosion.
Product Page this Question was Asked From
Pollak Black Plastic, 7-Pole, RV Blade-Style Trailer Socket - Vehicle End
- Custom Fit Vehicle Wiring
- Trailer Hitch Wiring
- Vehicle End Connector
- 7 Blade
- Plug Only
- Pollak
more information >
Featured Help Information
Miscellaneous Media
Continue Researching
- Shop: Trailer Hitch
- Q&A: How to Connect Factory Wiring on 2008 GMC Sierra 2500 HD to Pollak Twist-In 7-Way # PK11916
- Shop: Trailer Wiring
- Shop: Curt Trailer Hitch Receiver - Custom Fit - Class IV - 2"
- Shop: LCD Digital Circuit Tester
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Video: Feature Breakdown: LCD Digital Circuit Tester
- Article: Trailer Wiring Diagrams
- Q&A: NC Code on Tekonsha Prodigy Brake Controller After Installing 2nd 7-Way Trailer Connector
- Q&A: Fuse Locations for Trailer Lights on 2008 GMC Sierra
- Q&A: Trailer Brakes only Work When the Manual Override Lever is Activated on a P2 Brake Controller
- Q&A: Brake Controller Wire Functions By Wire Color
- Q&A: Installing Aftermarket Brake Controller on 2012 GMC Sierra With Factory Integrated Brake Controller
- Q&A: Troubleshooting No Power At The Factory Trailer Plug
- Shop: Hook Probe Circuit Tester
- Shop: Twist-in, 7-Pole, RV-Style Trailer Connector for Chevy and GMC Vehicles - Vehicle End
- Shop: Pollak Replacement 7-Pole, RV-Style Trailer Connector Socket - Vehicle End
- Video: Curt T-Connector Vehicle Wiring Harness Review C56040
- Shop: Curt Powered Tail Light Converter with 4-Pole Flat Trailer Connector
- Search Results: trailer hitch
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Shop: Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires
- Search Results: trailer wiring
- Search Results: trailer tires and wheels
- Video: The Low-Down on the Curt Powered Tail Light Converter with 4-Pole Flat Trailer Connector
- Search Results: trailer jack
- Article: How to Measure for Trailer Hitch Drop
- Shop: Brake Controller
- Article: How to Choose the Right Trailer Hitch Class
- Shop: Base Plate for Tow Bar
on Custom Fit Vehicle Wiring
