GMC 2004 Yukon XL Owner's Manual page 121

Tow/Haul Mode
Your vehicle may be equipped with a Tow/Haul mode.
If so, the selector button is located on the end of
the column shift lever. You can use this feature to assist
when towing or hauling a heavy load. See Towing a
Trailer on page 4-63 for more information.
The Tow/Haul mode also interacts with the Autoride™
feature, if your vehicle is so equipped, to enhance
the ride when trailering or with a loaded vehicle.
See Autoride™ on page 4-62.
When Tow/Haul mode is
selected the Tow/Haul
indicator light will
illuminate.
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