The interior lighting system consists of two subsystems
- Interior lamps
- Demand lamps
The interior lamps subsystem consists of the puddle lamps, overhead console, second row, third row (if equipped) dome lamps and luggage compartment lamp (if equipped). The smart junction box (SJB) provides the power circuit for the interior courtesy lamps.
The demand lamps subsystem consists of the overhead console, second row, third row (if equipped) dome lamps and the LH and RH vanity mirror lamps. Each of these lamps are switched individually and share a common ground circuit.
On vehicles equipped with autolamps, the illuminated entry feature does not turn the interior lamps on if the SJB determines it is daytime based on input from the light sensor.
Refer to SYSTEM WIRING DIAGRAMS - FIVE HUNDRED , SYSTEM WIRING DIAGRAMS - FREESTYLE or SYSTEM WIRING DIAGRAMS - MONTEGO for schematic and connector information.
SPECIAL TOOLS REFERENCE 73111 Automotive Meter 105-R0057 or equivalent Worldwide Diagnostic System (WDS) Vehicle Communication Module (VCM) with appropriate adapters, or equivalent diagnostic tool
Principles of Operation
When the smart junction box (SJB) detects a request for lighting, it turns on the interior lamps by supplying power to the lamps. The request for lighting can be an open door 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. The 4 door ajar switches are normally closed when the doors are closed. The liftgate/decklid ajar switch is normally open when the doors are closed. All door ajar switches receive voltage from the SJB and each has its own ground circuit.
The instrument panel dimmer switch receives a voltage signal from the SJB. The instrument panel dimmer switch provides variable resistance for backlighting the instrument cluster and a toggle on/off function for the interior lights.
Note. On vehicles equipped with autolamps, the interior lights do not turn on for the illuminated entry feature if the SJB determines it is daytime.
The RKE receiver is contained inside the SJB. When the SJB receives an unlock request from the RKE transmitter, it unlocks the doors and turns on the interior lamps.
Normal Operation
The interior lamps are activated by any door, decklid/liftgate, dimmer control switch, or remote keyless entry (RKE). When the smart junction box (SJB) receives an interior lamps on request, it grounds the interior lamp relay (internal to the SJB) and provides voltage to the interior lamps through circuit 53 (BK/LB). The interior lamps are provided ground through circuit 1205 (BK).
When the dimmer control switch is rotated to the interior lamp detent position, ground is provided to the smart junction box (SJB) through circuit 1404 (YE).
When any door or decklid/liftgate is ajar, the smart junction box (SJB) provides voltage to the individual interior lamps through circuit 53 (BK/LB). Ground for the lamps is provided through circuit 1205 (BK).
When any door decklid/liftgate is ajar, the smart junction box (SJB) provides voltage to the individual puddle lamps through circuit 2010 (YE/RD). Ground for the lamps is provided through circuit 1205 (BK).
Ground for the ajar switches is provided through circuit 1205 (BK). When any door or decklid/liftgate is ajar, the ground circuit to the smart junction box (SJB) is interrupted. The open circuit signals the SJB to illuminate the interior lamps. Also, the dimmer control switch provides an input to the SJB to request interior lamps. Circuit 1404 (YE) is monitored by the SJB, when this circuit is grounded, it signals the SJB to illuminate the interior lamps. The SJB provides voltage to the individual lamps through circuit 53 (BK/LB)
When any door, the decklid, or the liftgate is opened, the ajar switch opens the circuit to the smart junction box (SJB). The SJB monitors the ajar circuits, and based on the ajar status, the SJB will provide power to the interior lamps through the courtesy lamp relay.
The battery saver relay, integral to the smart junction box (SJB), provides power to the demand lamps. Any demand lamp switch, when activated, provides power to the selected demand lamp. The demand lamps are energized anytime the SJB activates the battery saver relay. The SJB grounds the battery saver relay, and when the relay is energized, voltage is supplied to the demand lamp circuits on circuit 705 (LG/OG).
During the demand lighting function, the smart junction box (SJB) provides a ground for the battery saver relay. The battery saver relay provides power to circuit 705 (LG/OG). Circuit 705 (LG/OG) provides power to each demand lamp switch and when activated provides power to the selected demand lamp. The demand lamps are grounded through circuit 1205 (BK).
When the unlock button is pressed on the remote keyless entry (RKE) transmitter, or the unlock code is entered on the remote keypad, a signal is sent to the smart junction box (SJB). The SJB then activates the courtesy lamp relay, which when activated supplies voltage to the interior lamps.
Vehicles equipped with autolamps do not turn on the interior lamps for the illuminated entry feature if the SJB determines it is daytime.