2003 GMC Safari Owner's Manual - Page 208

Tow/Haul Mode The tow/haul mode is a feature that assists when pulling a heavy trailer. The purpose of the tow/haul mode is: 0 The tow/haul mode for hauling a heavy trailer is most useful under the following conditions: 0 to reduce the frequency of shifts when pulling a heavy trailer. to provide the same shift feel when pulling a heavy trailer as when the vehicle is unloaded. to reduce the need to change throttle position when pulling a heavy trailer. When driving through hilly terrain at speeds below 55 mph (88 km/h). When driving in low speed or stop and go traffic below 55 mph (88 km/h). When driving in parking lots. 0 0 This feature is turned on or off by pressing a button on the column shift lever. When the feature is on, a light on the instrument panel will illuminate to indicate that the tow/haul mode has been selected. See Tow/Haul Mode Light on page 3-36. The tow/haul mode is automatically turned off each time the vehicle is started. The tow/haul mode is most effective when the vehicle and trailer combined weight is at least 75% of the Gross Vehicle Weight Rating (GVWR) and the maximum trailer weight rating for the vehicle. Operating in the tow/haul mode when not pulling a heavy trailer will not cause damage to the vehicle, but you may experience reduced fuel economy and undesirable performance from the engine and transmission. The tow/haul mode should be used only when pulling a heavy trailer. Weight of the Trailer How heavy can a trailer safely be? It dependson how you plan to use your rig. For example, speed, altitude, road grades, outside temperature and how much your vehicle is used to pull a trailer are all important. And, it can also depend on any special equipment thatyou have on your vehicle. 4-33