The ignition switch helps start and shut off the engine in your 1991 Geo Prizm. But a worn -ut switch may fail to connect or disconnect the starter solenoid properly. In that case, you need to remove the failed switch and install a new one. The switch is mounted on the steering column of your Prizm, which makes it easier for you to access the unit by removing a few components, using a few simple tools.
Open the hood and disconnect the black (negative) battery cable, using a wrench.
Unscrew the two fasteners from behind the steering wheel holding the steering pad and horn button. Use a Phillips-head screwdriver.
Remove the steering pad and horn button assembly from the steering wheel.
Unfasten the steering wheel retaining nut with a ratchet, ratchet extension and socket and remove the washer from under the retaining nut.
Make a small mark on the steering column shaft and another one on the base of the steering wheel, right in front of the first mark. You will use these marks as reference points to install the steering wheel in the same exact position on the steering column shaft during the reassembly process. Use a white marker.
Install a steering wheel puller on the steering wheel and dislodge the steering wheel from the steering column.
Unfasten the lower instrument panel trim, using a ratchet, ratchet extension and socket. Carefully tilt the trim down and forward and disconnect by hand the small duct going from the back of the trim panel to the air duct.
Unscrew the two bolts holding the upper and lower steering column covers with a Phillips-head screwdriver.
Unscrew the bolts holding the multifunction switch to the steering column and lift it out of the way, but do not unplug the electrical connector. Use a ratchet, ratchet extension and socket.
Insert the ignition key into the lock cylinder and turn the key to the accessory ("Acc") position.
Introduce the tip of a scratch awl into the access hole on top of the ignition lock cylinder. Push the pin inside the hole with the awl and pull the ignition key to remove the lock cylinder from the assembly. Make sure the lock cylinder and the column lock remain in the "Acc" position during the reassembly process.
Look carefully how the ignition switch fits on the column assembly so that you install the new switch in the same position. Unscrew the switch mounting screw, using a ratchet, ratchet extension and socket. Unplug the electrical connectors and remove the switch from the column assembly. When reassembling components, tighten the steering wheel retaining nut to 25 ft-lbs. with a torque wrench.
