Operation CHARM: Car repair manuals for everyone.

Principles of Operation

PRINCIPLES OF OPERATION

The smart junction box (SJB) supplies voltage to the interior lighting system. The interior lighting system illuminates the courtesy lamps to enhance visibility of the interior while a vehicle door is open or ajar, and the vehicle speed is less than 15 km/h (9 mph). The SJB controls all interior lighting functions and timing by monitoring inputs from the door ajar switches and vehicle speed.

Interior Lighting Delay
The interior lighting delay feature provides temporary illumination of the courtesy lamps after the doors are opened and then closed. The interior lighting delay feature will keep the courtesy lamps on for a period of 25 seconds. If during the 25 second delay time the SJB detects that the ignition has been turned ON, or if the vehicle is locked using the remote keyless entry (RKE) transmitter or the keypad, the courtesy lamp illumination will be discontinued.

Illuminated Entry
The illuminated entry requests the courtesy lamps to be illuminated when the ignition is OFF and either the RKE transmitter UNLOCK button is pressed, or the vehicle is unlocked using the keypad. The illuminated entry requests the courtesy lamps off after 25 seconds have elapsed, the ignition is switched to ON, the RKE transmitter LOCK button is pressed, or the vehicle is locked using the keypad.

Illuminated Exit
The illuminated exit requests the courtesy lamps be illuminated for 25 seconds when all doors are closed and the ignition key is removed from the ignition lock cylinder. The illuminated exit will request the courtesy lamps be deactivated when the ignition key is inserted into the ignition lock cylinder, or 25 seconds have elapsed.

Theater Lighting
The theater lighting option ramps-up the courtesy lamps over 0.7 seconds when courtesy lamp activation is requested. The theater lighting feature ramps-down the courtesy lamps over 1.7 seconds when interior lighting deactivation is requested by any feature other than the panic alarm or battery saver.

Interior Lamp Arbitrator
The interior lamp arbitrator (located in the SJB) chooses between the interior lighting, interior mode, interior lighting delay, illuminated entry, illuminated exit and battery saver to determine which feature has precedence of activating and deactivating the interior lamps. The features are prioritized as follows: battery saver, interior mode, interior lighting, interior light delay, illuminated entry, and illuminated exit.

Battery Saver
The battery saver is internal to the SJB and provides automatic shutoff of the demand lamps (vanity lamps, map lamps and glove compartment lamp) and courtesy lamps after a period of 30 minutes (10 minutes if the lights are on due to a door ajar) has elapsed in order to save battery voltage. A timer in the SJB starts when the ignition is turned to the OFF position. When the time-out period for the lamps has elapsed, the voltage is automatically shutoff to the lamps by the battery saver. While the battery saver has voltage disabled, if the ignition is turned to any position other than OFF, a door becomes ajar, the UNLOCK button of the RKE transmitter is pressed, or the keypad is used to lock the vehicle, the battery saver will restore voltage and start the timer again.