2002 GMC Yukon Owner's Manual - Page 100

Liftgate CAUTION: It can be dangerous to drive with the liftgate glass, liftgate or rear doors 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 glass, liftgate or rear doors open or if electrical wiring or other cable connections must pass through the seal between the body and the liftgate glass, liftgate or rear doors: D Make sure all other windows are shut. D Turn the fan on your heating or cooling system to its highest speed with the setting on VENT or OUTSIDE AIR. 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. Liftgate Glass and Liftgate To open a mechanical lock system from the outside, insert the key into the lock and turn it counterclockwise to unlock the glass and liftgate. The liftgate glass can be opened using the button on the liftgate after the doors have been unlocked. This can be done by using either the power door locks or the remote keyless entry system. To open the entire liftgate, lift the handle located in the center of the door. To lock a power lock system from the outside, insert the key into the lock button and turn clockwise. All doors will lock. You may also use the keyless entry system or the power door locks to lock the liftgate and liftgate glass. 2-14