2007 Chevrolet Tahoe Owner's Manual - Page 140

Ignition Positions Notice: Using a tool to force the key from the ignition switch could cause damage or break the key. Use the correct key and turn the key only with your hand. Make sure the key is all the way in. If it is, turn the steering wheel left and right while you turn the key hard. If none of this works, then your vehicle needs service. B (ACCESSORY): This position lets you use things like the radio and the windshield wipers when the engine is off. Lengthy operation of features such as the radio in the ACCESSORY ignition position and the RUN position may drain the battery and prevent your vehicle from starting. Do not operate your vehicle in the ACCESSORY ignition position for a long period of time. C (RUN): This is the position for driving. It is the position the switch returns to after the engine starts, and you release the key. The battery could be drained if you leave the key in the ACCESSORY or RUN position with the engine off. You may not be able to start your vehicle if the battery is allowed to drain for an extended period of time. D (START): This position starts the engine. Use the key to turn the ignition switch to four different positions. A (LOCK): This position locks the ignition and transmission. It is a theft-deterrent feature. You will only be able to remove the key when the ignition is turned to LOCK. 140