2004 GMC Envoy Owner's Manual - Page 86

Ignition Positions Notice: If your key seems stuck in LOCK and you can not turn it, be sure you are using the correct key; if so, is it all the way in? Turn the key only with your hand. Using a tool to force it could break the key or the ignition switch. If none of these 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. Notice: Lengthy operation of features such as the radio in the accessory ignition 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. Use the key to turn the ignition switch to four different positions. A (LOCK): This position locks the ignition and transmission. It's a theft-deterrent feature. You will only be able to remove the key when the ignition is turned to LOCK. D (START): This position starts the engine. 2-20