GMC 1994 Sonoma Owner's Manual page 68

NOTICE:
Driving with the parking brake on can cause your rear brakes to
overheat. You may have to replace them, and you could also
damage other parts of your vehicle.
If you are on a hill:
See "Parking on Hills" in the Index. That section
shows how to turn your front wheels.
If you are towing a trailer and are parking on any hill: See "Towing a
Trailer" in the Index. That section shows what to do first to keep the trailer
from moving.
Shifting Info "Pyy (Park)
(AutomaticTransmission Models Only)
1. Hold the brake pedal down with your right foot and set the parking
brake.