Pinpoint Test C: The Interior Courtesy Lamp(s) Are Inoperative
Interior Lighting
Pinpoint Test C: The Interior Courtesy Lamp(s) Are Inoperative
Refer to Wiring Diagram Set 89, Interior Lamps for schematic and connector information. [1][2]Diagrams By Number
Normal Operation
Power is supplied to the interior courtesy lamps and cargo lamp by the Smart Junction Box (SJB) fuse 9 (15A). Based on the input status, the SJB (Smart Junction Box) supplies voltage to the interior courtesy lamps.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Interior lamp
- SJB (Smart Junction Box)
PINPOINT TEST C : THE INTERIOR COURTESY LAMP(S) ARE INOPERATIVE
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
C1 CHECK THE OPERATION OF ALL THE INTERIOR COURTESY LAMPS
- Ignition OFF.
- Push up the instrument panel dimmer switch to the second up detent and observe the interior courtesy lamps.
Are all the interior courtesy lamps inoperative?
Yes
VERIFY the SJB (Smart Junction Box) fuse 9 (15A) is OK. If OK, GO to C4.
If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. After the repair: [1][2]Diagrams By Number
If no DTCs are present, TEST the system for normal operation.
If DTC B106E is present, CLEAR the DTCs and REPEAT the self-test (required to enable the interior courtesy lamp output driver if DTC B106E is present). TEST the system for normal operation.
If DTC B106F is present, INSTALL a new SJB (Smart Junction Box). TEST the system for normal operation.
No
GO to C2.
C2 CHECK FOR VOLTAGE TO THE INTERIOR LAMP
- Push the instrument panel dimmer switch down out of the DOME LAMP position.
- Disconnect: Inoperative Lamp.
- Push up the instrument panel dimmer switch to the second up detent.
- Measure the voltage between the inoperative lamp, harness side and ground as follows:
Inoperative Lamp Connector-Pin Circuit Front C930-3 VLN33 (GY/VT) Front (MKZ with ambient lighting) C9035-3 VLN33 (GY/VT) Rear C901-1 VLN33 (GY/VT) LH scuff plate C3251-1 VLN33 (GY/VT) RH scuff plate C3250-1 VLN33 (GY/VT)
Is the voltage greater than 10 volts?
Yes
GO to C3.
No
REPAIR circuit VLN33 (GY/VT) for an open. TEST the system for normal operation.
C3 CHECK FOR VOLTAGE TO THE INTERIOR LAMP USING THE CONNECTOR GROUND
- Measure the voltage between the inoperative interior lamp connector, harness side as follows:
Inoperative Lamp Connector-Pin/ Circuit Connector-Pin/ Circuit Front C930-3 VLN33 (GY/VT) C930-1 GD139 (BK/YE) Front (MKZ with ambient lighting) C9035-3 VLN33 (GY/VT) C9035-1 GD139 (BK/YE) Rear C901-1 VLN33 (GY/VT) C901-2 GD139 (BK/YE) LH scuff plate C3251-1 VLN33 (GY/VT) C3251-3 GD126 (BK/WH) RH scuff plate C3250-1 VLN33 (GY/VT) C3250-3 GD126 (BK/WH)
Is the voltage greater than 10 volts?
Yes
INSTALL a new interior lamp for the lamp in question. REFER to Interior Lamp - Front or Interior Lamp - Rear . TEST the system for normal operation.
No
REPAIR the ground circuit in question for an open. TEST the system for normal operation.
C4 BYPASS THE SJB (Smart Junction Box)
- Ignition OFF.
- Disconnect: SJB (Smart Junction Box) C2280A.
- NOTE: If the jumper wire fails, refer to the Wiring Diagrams to identify the possible causes of the circuit short. After the repair: If no DTCs are present, test the system for normal operation. If DTC B106E is present, clear the DTCs and repeat the self-test (required to enable the courtesy lamp output driver if DTC B106E is present). Test the system for normal operation. If DTC B106F is present, install a new SJB (Smart Junction Box). Test the system for normal operation. [1][2]Diagrams By Number
Connect a fused jumper wire between the SJB (Smart Junction Box) C2280A-9, circuit VLN33 (GY/VT), harness side and battery positive.
Do the courtesy lamps illuminate?
Yes
REMOVE the jumper wire. GO to C5.
No
REMOVE the jumper wire. REPAIR circuit VLN33 (GY/VT) for an open. CLEAR the DTCs. REPEAT the self-test.
C5 CHECK FOR CORRECT SJB (Smart Junction Box) OPERATION
- Disconnect all the SJB (Smart Junction Box) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB (Smart Junction Box) connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new SJB (Smart Junction Box). TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.