2010 Buick Enclave Owner's Manual - Page 293

Driving and Operating Tow/Haul Mode Tow/Haul assists when pulling a heavy trailer or a large or heavy load. The purpose of the Tow/Haul mode is to: . 9-49 Reduce the frequency and improve the predictability of transmission shifts. Provide the same solid shift feel as when the vehicle is unloaded. Improve control of vehicle speed while requiring less throttle pedal activity. Increase the charging system voltage to assist in recharging a battery installed in a trailer. 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 comes 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). See Trailer Towing on page 9‑52. Tow/Haul is most useful when pulling a heavy trailer or a large or heavy load under the following driving conditions: ... Travelling through rolling terrain. Travelling in stop and go traffic. Travelling 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 will not cause damage but there is no benefit. Such a selection when unloaded may result in unpleasant engine and transmission driving characteristics and reduced fuel economy.