See also:

Trailer Wiring Harness
The vehicle is equipped with one of the following wiring harnesses for towing a trailer or hauling a slide-in camper. ...

Tips and Troubleshooting Chart
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Trailer Gain Adjustment Procedure
Trailer Gain should be set for a specific trailering condition and must be adjusted any time vehicle loading, trailer loading, or road surface conditions change. Setting the Trailer Gain properly is ...