Ignition Switch: Description and Operation

IGNITION SWITCH AND KEY LOCK CYLINDER

The ignition switch is located on the steering column. The Key-In-Switch is located in the ignition switch module. For removal/installation of either the key lock cylinder or ignition switch, refer to Ignition Switch and Key Cylinder Service and Repair.

On vehicles equipped with an automatic transmission, a cable connects an interlock device within the steering column assembly to the transmission floor shift lever. This interlock device is used to lock the transmission shifter in the PARK position when the key is in the LOCKED or ACCESSORY position. The interlock device is not serviceable. If repair is necessary, the steering column assembly must be replaced. Refer to Steering for procedures. The shifter interlock cable can be adjusted or replaced. Refer to Transmissions for procedures.


CIRCUIT OPERATION
Circuit A1 from fuse 2 and circuit A2 from fuse 3, in the power distribution center (PDC), supply battery voltage to the ignition switch. Depending upon position, the ignition switch powers circuits A21, A22, A31, A41, G9, G26, and G99.

Start Position
In the START position, the ignition switch connects circuit A1 to circuit A21 and circuit A2 to circuit A41.
Additionally in the START position, the case grounded ignition switch provides ground for the brake lamp switch and the warning lamps in the instrument cluster.

Start Or Run Position
In the START or RUN position, the ignition switch connects circuit A1 to circuit A21.

Run (Only) Position
When the ignition switch is in the RUN position, it connects circuit A1 to circuit A21 and circuit A2 to circuit A22.

Accessory Or Run Positions
In the ACCESSORY or RUN positions, the ignition switch connects circuit A1 to circuit A31.