Courtesy Lamp: Description and Operation

Generic Electronic Module (GEM)
The Generic Electronic Module (GEM) receives inputs from the following:
^ door ajar switches
^ liftgate ajar switch (wagon)
^ liftgate glass switch (wagon)
^ headlamp switch
^ keyless entry keypad switches
^ the Powertrain Control Module (PCM) (vehicle speed signal)
^ ignition switch
^ remote keyless entry transmitter

The GEM uses these inputs to control the output to the battery saver relay and interior lamp relay. Both relays are integral to the Central Junction Box (CJB) and cannot be accessed directly.

Interior Lighting Systems
The GEM grounds the battery saver relay and interior lamp relay coils when any door ajar switch or the headlamp switch is closed. The interior lamp relay then supplies power to the interior lamp circuit. Vehicle speed must be less than 15 kph (9 mph) for the GEM to ground the interior lamp relay. The interior lamps will remain illuminated for a period of up to 25 seconds after all doors are closed or until the ignition is switched from the OFF position, or the GEM receives a vehicle speed signal. Actuating the interior lights from the headlamp switch will operate at any time.

Illuminated Entry
Illuminated entry is activated when a keyless entry keypad switch provides ground on the GEM input or when the GEM receives an unlock signal from the remote keyless entry key fob. The GEM then provides ground to the battery saver and interior lamp relay coils. Illuminated entry is deactivated when the GEM receives a lock signal from the remote keyless entry key fob or if the GEM receives ground inputs from the keyless entry keypad switch lock code. Illuminated entry will also be deactivated when the GEM receives input voltage from the ignition switch.

Battery Saver
The battery saver is activated when the GEM is not receiving voltage input from the ignition switch (off position). The GEM will then provide ground to the battery saver relay coil for a maximum of 30 minutes depending on the state of the interior lamp switch inputs to the GEM. The energized battery saver relay switches voltage to the demand lamp circuit and the interior lamp relay coil. After time-out, the GEM removes ground to the battery saver relay disabling the demand lamp circuit.

Puddle Lamps
The puddle lamp relay operates reverse from the battery saver relay and the interior lamp relay. The puddle lamp relay coil receives voltage when the ignition switch is in the START or RUN position, which disables the circuit to the puddle lamps.