1996 GMC Yukon Owner's Manual - Page 74

Ignition Positions Use your key to start your vehicle. The key lets you turn the ignition switch to five different positions. LOCK (Bj: This position locks your ignition, steering wheel and transmission. It's a theft-deterrent feature. You will only be able to remove your key when the ignition is turned to LOCK. OFF (C): This position lets you turn off the engine but still turn the steering wheel. It doesn't lock the steering wheel like LOCK. Use OFF if you must have your vehicle in motion while the engine is off (for example, if your vehicle is being pushed). RUN (D): This is the position for driving. C I START (E): This position starts your engine. NOTICE: -b m .. 7 ACCESSORY (A): This position lets you use things like the radio and the windshield wipers when the engine is off. Push in the key and turn it toward you. Your steering wheel will remain locked, just as it was before you inserted the key. If your key seems stuck in LOCK and you can't turn it, be sure itis all the way in. If it is, then turn the steering wheel left and right while you turn thekey hard. But turn the only with key your hand. Using a tool to force it could break the key or theignition switch.If none of this works, then your vehicle needs service. 2-10