Basic Trailer Wiring
All regular, extended cab and crew cab pickups have a seven-wire trailer towing harness.
For vehicles not equipped with heavy duty trailering, the harness is secured to the vehicle's frame behind the spare tire mount. The harness requires the installation of a trailer connector, which is available through your dealer.
If towing a light-duty trailer with a standard four-way round pin connector, an adapter is available from your dealer.
See also:
Four-Wheel-Drive Light
For vehicles equipped with the four-wheel-drive light, it comes on when a vehicle with a manual transfer case is shifted into four-wheel drive and the front axle engages.
Some delay between the shi ...
Customer Assistance Offices (U.S. and Canada)
GMC encourages customers to call the toll-free number for assistance.
However, if a customer wishes to write or e-mail GMC, the letter should be addressed to:
United States
GMC Customer Assistance ...
Courtesy Lamps
The courtesy lamps automatically come on when a door is opened.
The lamps can also be turned on manually by fully turning the instrument panel brightness control clockwise.
The reading lamps, locate ...