2000 GMC Yukon Owner's Manual - Page 81

From the inside, to lock the door, slide the lever rearward. To unlock the door, slide the lever forward. If your vehicle has this power door lock switch, press the bottom of the switch on either front door to lock all the doors at once. Power Door Locks (If Equipped) If your vehicle has this power door lock switch, press the raised side of the switch, marked "L" on either front door to lock all the doors at once. Press the top of the switch to unlock all the doors at once. On the passenger side of the rear cargo door or liftgate opening trim there is a power lock switch which can be used to lock or unlock all of the doors. Press the recessed side of the switch marked "U" to unlock all the doors at once. 2-4