The interior lighting system consists of 2 subsystems: the interior courtesy lamps and the demand lamps.
The interior courtesy lamp subsystem consists of the puddle, overhead console, second row, third row (if equipped) dome lamps and cargo 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.
Refer to INTERIOR LIGHTS (Montego), INTERIOR LIGHTS (Five Hundred), or INTERIOR LIGHTS (Freestyle) for schematic and connector information.
Principles of Operation
When the 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.
The RKE receiver is contained inside the SJB. When the SJB receives an unlock request from an RKE transmitter, it unlocks the doors and turns on the interior lamps.
Normal Operation
Under normal operation, when the smart junction box (SJB) turns ON the interior lamps, it provides voltage to the individual lamps through circuit 53 (BK/LB) (courtesy) or 705 (LG/OG) (demand). Ground for the lamps is provided through circuit 1205 (BK).
Under normal operation, when the dimmer control is rotated to the interior lamp detent position, ground is provided to the smart junction box (SJB) through circuit 1404 (YE).
Under normal operation, when any door, liftgate or decklid is ajar the smart junction box (SJB) turns ON the interior lamps, providing voltage to the individual lamps through circuit 53 (BK/LB). Ground for the lamps is provided through circuit 1205 (BK).
Under normal operation, when any door, liftgate or decklid is ajar or the smart junction box (SJB) turns ON the puddle lamps, providing voltage to the individual lamps through circuit 2010 (YE/RD). Ground for the lamps is provided through circuit 1205 (BK).
Under normal operation, ground for the ajar switches are provided through circuit 1205 (BK). When any door, liftgate or decklid is ajar, ground to the smart junction box (SJB) is interrupted. The SJB provides voltage to the individual lamps through circuit 53 (BK/LB). When any door, liftgate or decklid is closed, ground is provided to the SJB through the circuits below.
Under normal operation, ground for the ajar switches is provided through circuit 1205 (BK). When any door, liftgate or decklid is ajar, ground to the smart junction box (SJB) is interrupted. The SJB provides voltage to the individual lamps through circuit 53 (BK/LB). When any door, liftgate or decklid is closed ground is provided to the SJB through the circuits below.
- LH front door ajar switch circuit 1312 (LG/BK).
- RH front door ajar switch circuit 1314 (YE/LG).
- LH rear door ajar switch circuit 1742 (VT/LG).
- RH rear door ajar switch circuit 1754 (RD).
- Liftgate ajar switch circuit 700 (WH/VT).
- Decklid ajar switch circuit 700 (WH/VT).
Under normal operation, the smart junction box (SJB) provides voltage to the individual demand lamps through circuit 705 (LG/OG). Ground for the lamps is provided through circuit 1205 (BK).
Under normal operation, the smart junction box (SJB) provides voltage to the individual demand lamps through circuit 705 (LG/OG). Ground for the lamps is provided through circuit 1205 (BK).
Under normal operation, when the smart junction box (SJB) turns ON the interior lamps, it provides voltage to the individual lamps through circuit 53 (BK/LB). Ground for the lamps is provided through circuit 1205 (BK).