Interior Lighting

INTERIOR LIGHTING

The interior lighting system consists of the following:
- Interior lamp
- Instrument panel dimmer switch
- Door ajar switch (located on both the front and rear door latches)
- Smart junction box (SJB) (also known as the generic electronic module [GEM])

Principles of Operation

Interior Lighting

NOTE: The smart junction box (SJB) is also known as a generic electronic module (GEM)

When the SJB/GEM detects a request for lighting, it turns on the interior lamp by supplying power to the lamp. The request for lighting can be a signal from a door ajar switch, an interior lighting on command from the instrument panel dimmer switch or an unlock command from a remote keyless entry (RKE) transmitter. The door ajar switches are hard-wired directly to the SJB/GEM. The door ajar switches are normally open when the doors are closed. All door ajar switches receive a voltage signal from the SJB/GEM and each has its own ground circuit. The instrument panel dimmer switch receives a voltage signal from the SJB/GEM and has its own ground circuit. The instrument panel dimmer switch provides variable resistance for backlighting the instrument cluster and a toggle on/off function for the courtesy lamp.

The inputs are:
- Ignition switch position
- LH front door ajar switch
- RH front door ajar switch
- LH rear door ajar switch
- RH rear door ajar switch
- RKE unlock signal

For additional door ajar switch information, see SECURITY AND LOCKS. Security and Locks
The output is the interior lamp relay.

Illuminated Entry (Option)
The illuminated entry feature requests the interior lamp on when the ignition switch is in the OFF position and the operator activates an external unlock feature (key fob). The illuminated entry feature requests the interior lamp off when 25 seconds have elapsed, the ignition transitions out of the OFF position, or the customer activates an external lock feature.

The inputs are:
- Ignition switch position
- Unlock request from the RKE transmitter

The output is the interior lamp relay.

Demand Lamps
The demand lamp function can be operated independently.
The demand lamps consist of a:
- Interior lamp
- Instrument cluster dimmer switch

The demand lamp is also controlled by the interior lighting arbitrator and the interior lamp relay.

Interior Lighting Arbitrator
The interior lighting arbitrator decides between the interior lighting, the illuminated entry lighting, and the battery saver features to determine which feature has precedence for turning on and off the interior light. This feature is internal in the SJB/GEM.

The output is the interior lamp relay.

Battery Saver
When the ignition is off, the battery saver timer feature provides timed automatic shut off of power to the interior lamp and the warning chimes. The battery saver has a time-out period of 5 minutes. The battery saver restores power to the interior lamp or resets the 5 minute timer if any of the following interactions are detected:
- The ignition is turned to any position other than OFF.
- Any door becomes ajar.
- Any button of a RKE transmitter which provides access to the vehicle is pressed (key fob).

The inputs are:
- Ignition switch position
- LH front door ajar switch
- RH front door ajar switch
- LH rear door ajar switch
- RH rear door ajar switch
- Any request from the RKE transmitter

The output is the interior lamp relay.