2007 Hummer H2 Owner's Manual - Page 130

Indicator lights in the buttons show which mode you are in. The indicator lights will come on briefly when you turn on the ignition and one will stay on. If the lights do not come on, you should take your vehicle to your dealer for service. An indicator light will flash while shifting the transfer case. It will remain on when the shift is complete. If for some reason the transfer case cannot make a requested shift, it will return to the last chosen setting. If the SERVICE 4WD message stays on, you should take your vehicle to your dealer for service. See "Service 4WD message" under Driver Information Center (DIC) on page 222. Shifting into Four-Wheel-Low Lock To shift into Four-Wheel-Low Lock, the ignition must be in RUN and the vehicle must be stopped or moving less than 3 mph (5 km/h) with the transmission in NEUTRAL (N). The preferred method for shifting into Four-Wheel Low is to have your vehicle moving 1 to 2 mph (1.6 to 3.2 km/h). Press and release the Four-Wheel-Low Lock button. You must wait for the Four-Wheel-Low Lock indicator light to stop flashing and remain lit before shifting your transmission in gear. Notice: Shifting the transmission into gear before the indicator light stops flashing could cause damage to the transfer case. Always wait until the indicator light stops flashing before putting the transmission back in gear. It is normal for your vehicle to have engagement noise and bump when shifting between Four-Wheel Low and Four-Wheel High or Four-Wheel-High Lock ranges or from NEUTRAL with the engine running. Shifting between Four-Wheel High and Four-Wheel-High Lock With the vehicle traveling less than 40 mph (64 km/h), press and release the Four-Wheel High or Four-Wheel-Low Lock button. The indicator light will flash while shifting. It will remain on when the shift is complete. It may be necessary to drive backwards for a short distance of 25 feet (7.5 m) to get the lock feature to disengage. 130