2009 Hummer H3T Owner's Manual - Page 190

4-8 Driving Your Vehicle Adjust your driving accordingly. See DIC Warnings and Messages on page 3-37 for more information. It is recommended to leave the system on for normal driving conditions, but it may be necessary to turn the system off if the vehicle is stuck in sand, mud, ice, or snow, and it is necessary to "rock" the vehicle to attempt to free it. See If Your Vehicle is Stuck in Sand, Mud, Ice, or Snow on page 4-33 for more information. When TCS has been turned off, this light comes on steady and TRAC OFF appears on the DIC. This light flashes when TCS is active. Press and release the TCS/StabiliTrak button again to turn the system back on. The TRAC OFF message then goes off. TCS automatically comes on whenever the vehicle is started and resets itself at each ignition cycle. Adding non-dealer/non-retailer accessories can affect the vehicle's performance. See Accessories and Modifications on page 5-3. Locking Rear Axle For vehicles with this feature, additional traction can be obtained from the rear wheels when traveling in off-road situations such as mud, snow, sand, steep hills and uneven terrain. The button used to turn this feature on or off is located on the instrument panel. To lock the rear axle, do the following: 1. Place the transfer case in the 4LO Lock mode. This is the only mode which will allow the rear axle to lock. See Full-Time Four-Wheel Drive on page 2-24 for more information regarding the transfer case and 4LO Lock mode. To turn the system off, press and release the TCS/StabiliTrak® button.