GM Service Manual Online
For 1990-2009 cars only

With the key in the ignition switch, you can turn it to four different positions.


Object Number: 1839829  Size: A3

Notice: If your key seems stuck in LOCK/OFF and you cannot turn it, be sure you are using the correct key; if so, is it all the way in? If it is, then turn the steering wheel left and right while you turn the key hard. 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 work, then your vehicle needs service.

(A) LOCK/OFF: This is the only position from which you can remove the key. This locks your steering wheel, ignition and automatic transmission. Push in the ignition switch as you turn the key toward you. If you have an automatic transmission, the ignition switch cannot be turned to LOCK/OFF unless the shift lever is in PARK (P).

Caution: On manual transmission vehicles, turning the key to LOCK/OFF will lock the steering column and result in a loss of ability to steer the vehicle. This could cause a collision. If you need to turn the engine off while the vehicle is moving, turn the key only to ACC/ACCESSORY. Do not push the key in while the vehicle is moving.

(B) ACC/ACCESSORY:  This position operates some of your electrical accessories, such as the radio, but not the ventilation fan. It unlocks the steering wheel and ignition. To move the key from ACC/ACCESSORY to LOCK/OFF, push in the key and then turn it to LOCK/OFF.

(C) ON/RUN:  This is the position the switch returns to after you start your engine and release the switch. The switch stays in the ON/RUN position when the engine is running. But even when the ignition is not running, you can use ON/RUN to operate your electrical accessories, including the ventilation fan and 115 volt power outlet, and to display some warning and indicator lights. The battery could be drained if you leave the key in the ACC/ACCESSORY or ON/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. When the engine starts, release the key. The ignition switch will return to ON/RUN for normal driving. When the engine is not running, ACC/ACCESSORY and ON/RUN allow you to operate some of your electrical accessories. A warning tone will sound if you open the driver's door when the ignition is still in ACC/ACCESSORY or LOCK/OFF and the key is in the ignition.

Key In the Ignition

Never leave your vehicle with the keys inside, as it is an easy target for joy riders or thieves. If you leave the key in the ignition and park your vehicle, a chime will sound, when you open the driver's door. Always remember to remove your key from the ignition and take it with you. This will lock your ignition and transmission. Also, always remember to lock the doors.

The battery could be drained if you leave the key in the ignition while your vehicle is parked . You may not be able to start your vehicle after it has been parked for an extended period of time.