2003 Hummer H2 Owner's Manual - Page 97

Liftgate CAUTION: It can be dangerous to drive with the liftgate open because carbon monoxide (CO) gas can come into your vehicle. You can't see or smell CO. It can cause unconsciousness and even death. If you must drive with the liftgate open or if electrical wiring or other cable connections must pass through the seal between the body and the liftgate: D Make sure all other windows are shut. D Turn the fan on your heating or cooling system to its highest speed and select the control setting that will force outside air into your vehicle. See "Comfort Controls" in the Index. D If you have air outlets on or under the instrument panel, open them all the way. See "Engine Exhaust" in the Index. To unlock the liftgate, use the unlock button on any of the power door lock switches or the keyless entry transmitter. To open the liftgate, pull the handle located in the center of the door. Lock the liftgate by using the lock button on any of the power door lock lock switches or the keyless entry transmitter. 2-15