GMC 2004 Sierra 1500 Pickup, Owner'S Manual, Page: 116 / 588

Ignition Positions
With the key in the ignition switch, you can turn it to four
different positions.
A (LOCK): This position locks your ignition when the
key is removed. The steering locks when equipped with
a manual transmission. It is a theft-deterrent feature.
You will only be able to remove your key when the
ignition is turned to LOCK
B (ACCESSORY): This position allows you to use
things like the radio, power windows and the windshield
wipers when the engine is off.
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CAUTION:
On manual transmission vehicles, turning the
key to LOCK 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 OFF. Do not press the key
release button while the vehicle is moving.
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.
C (RUN): This is the position for driving.
D (START): This position starts your engine.
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