Test B: The Courtesy Lamps Stay On Continuously

PINPOINT TEST B: THE COURTESY LAMPS STAY ON CONTINUOUSLY

Normal Operation
When any door or the liftgate is opened, the ajar switch (or the power liftgate module if equipped) opens the circuit to the smart junction box (SJB) to indicate a request for the courtesy lamps. When the instrument panel dimmer switch is rotated to the dome detent, ground is supplied on circuit CLN28 (GN/BU) to the SJB. The SJB monitors the ajar circuits and the dome input circuit. Based on the inputs, the SJB supplies voltage to the courtesy lamps on circuit VLN33 (GY/VT).

DTC B1320 (Driver Door Ajar Circuit Open) - is an on-demand DTC that sets when the SJB detects an open from the LH front door ajar circuit.

DTC B1328 (Passenger Door Ajar Circuit Open) - is an on-demand DTC that sets when the SJB detects an open from the RH front door ajar circuit.

DTC B1336 (Door Ajar RR Circuit Open) - is an on-demand DTC that sets when the SJB detects an open from the RH rear door ajar circuit.

DTC B1572 (Door Ajar LR Circuit Open) - is an on-demand DTC that sets when the SJB detects an open from the LH rear door ajar circuit.

DTC B1688 (Lamp Dome Input Circuit Short To Ground) - is an on-demand DTC that sets when the SJB detects a short to ground from the instrument panel dimmer switch circuit.

DTC B2077 (Liftgate Ajar Sw Circuit Failure) - is an on-demand DTC that sets when the SJB detects an open from the liftgate ajar circuit.

DTC B2A35 (Interior Lighting Output Circuit Open) - is an on-demand DTC that sets when the SJB detects a short to voltage from the courtesy lamp output circuit.

DTC B2718 (Liftgate/Decklid Ajar Output Short To Battery) - is a continuous and on-demand DTC that sets when the power liftgate module detects a short to voltage from the liftgate ajar input circuit to the SJB.

DTC B2721 (Liftgate/Decklid Ajar Output Short To Ground Or Open) - is a continuous and on-demand DTC that sets when the power liftgate module detects an open from the liftgate ajar input circuit to the SJB.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Door ajar switch
- Liftgate ajar switch
- Instrument panel dimmer switch (part of the headlamp switch)
- Power liftgate module
- SJB

B1-B3:

B3-B6:

B7-B10:

B10-B13:

B13-B15: