2008 GMC Sierra 1500 Pickup Owner's Manual - Page 301

Three important considerations have to do with weight: • the weight of the trailer • the weight of the trailer tongue • and the weight on your vehicle's tires Tow/Haul Mode Tow/Haul is a feature that assists when pulling a heavy trailer or a large or heavy load. The purpose of the Tow/Haul mode is to: • Reduce the frequency and improve the predictability of transmission shifts when pulling a heavy trailer or a large or heavy load. • Provide the same solid shift feel when pulling a heavy trailer or a large or heavy load as when the vehicle is unloaded. Press this button at the end of the shift lever to enable/disable the tow/haul mode. A light on the instrument panel will illuminate to indicate that tow/haul mode has been selected. • Improve control of vehicle speed while requiring less throttle pedal activity when pulling a heavy trailer or a large or heavy load. • Increase the charging system voltage to assist in recharging a battery installed in a trailer. 4-43