2009 GMC Acadia Owner's Manual - Page 283

Driving Your Vehicle 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: 4-31 • Reduce the frequency and improve the predictability of transmission shifts when pulling a heavy trailer or a large or heavy load. Press this button located on the console to turn on and turn off the Tow/Haul mode. The Tow/Haul light on the instrument panel will come on to indicate that Tow/Haul mode has been selected. Tow/Haul may be turned off by pressing the button again, at which time the indicator light on the instrument panel will turn off. The vehicle will automatically turn off Tow/Haul every time it is started. Tow/Haul is designed to be most effective when the vehicle and trailer combined weight is at least 75 percent of the vehicle's Gross Combined Weight Rating (GCWR). • Provide the same solid shift feel when pulling a heavy trailer or a large or heavy load as when the vehicle is unloaded. • Improve control of vehicle speed while requiring less throttle pedal activity when pulling a heavy trailer or a large or heavy load. See Weight of the Trailer earlier in this section. Tow/Haul is most useful under the following driving conditions: • When pulling a heavy trailer or a large or heavy load through rolling terrain. • When pulling a heavy trailer or a large or heavy load in stop and go traffic. • When pulling a heavy trailer or a large or heavy load in busy parking lots where improved low speed control of the vehicle is desired. Operating the vehicle in Tow/Haul when lightly loaded or with no trailer at all will not cause damage. However, there is no benefit to the selection of Tow/Haul when the vehicle is unloaded. Such a selection when unloaded may result in unpleasant engine and transmission driving characteristics and reduced fuel economy. Tow/Haul is recommended only 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.