Principles of Operation

Steering Column Switches

Principles of Operation

NOTE: The Smart Junction Box (SJB) is also identified as the Generic Electronic Module (GEM).

Steering Column Switches

The steering column switches include the ignition switch, the multifunction switch (high beam/low beam, flash-to-pass, turn signal and windshield wiper) and the key release interlock actuator.

Ignition Switch

The ignition switch is controlled by the ignition lock cylinder with a key. When the ignition lock cylinder is turned using the key, a mechanical connection positions the ignition switch to the selected position and allows the ignition switch to send voltage to the Battery Junction Box (BJB) and the SJB. The ignition switch also contains a key-in ignition system that allows the SJB to detect when the key has been inserted in the ignition switch. This information is used by the SJB for the brake shift interlock system. The ignition switch and cylinder are part of the steering column lock module and can be serviced separately. The available ignition switch positions are:

- OFF
- ACC
- RUN
- START

Multifunction Switch

The multifunction switch controls the various components (high beam headlamps, flash-to-pass, turn signal and windshield wiper) by grounding certain SJB circuits and wiper motor circuits. When the SJB detects the specific ground, it sends a voltage to the appropriate component to activate it. The SJB controls the high beam headlamps, the flash-to-pass and the turn signals. The high beam headlamp and the turn signal portion are normally open switches that close when activated. The flash-to-pass switch is a momentary contact switch that grounds the SJB high beam headlamp circuit. The windshield wipe and wash functions are controlled directly by the multifunction switch, wiper and washer motor.

Key Release Interlock Actuator

The key release interlock actuator (also known as the key inhibit solenoid) is an electronically controlled solenoid that prevents the ignition key from being removed from the ignition cylinder unless the transmission selector lever is in the PARK position. The actuator is part of the steering column lock module and is mounted opposite the ignition cylinder. If a new actuator needs to be installed, then a the lock module must be installed. Refer to Steering Column Lock Module Steering Column Lock Module.

When the transmission selector lever is placed in a position other than PARK, the park detection switch closes and the key release interlock engages. This prevents the ignition key from being removed from the ignition cylinder.

When the transmission selector lever is placed in the PARK position, the park detection switch opens and the key release interlock disengages, allowing the ignition key to be removed from the ignition cylinder.