Buick 1993 LeSabre Owner's Manual page 71

Ignition Key Positions
I
Your square-headed key operates your ignition lock.
This lock gives you five different positions. Before you
put the key in, your ignition will be in the "Lock"
position. This position locks your ignition, steering
wheel and transaxle. It's a theft deterrent feature.
The other positions let you perform these functions:
ACC: Accessory lets you use things like the radio and
the windshield wipers when the engine is
off.
To get into
"Acc", push in the key and turn it toward you. Your
steering wheel will remain locked, just as it was before
you inserted the key.
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