Pinpoint Test C: The Interior Courtesy Lamp(s) Are Inoperative
Interior Lighting
Pinpoint Tests
Pinpoint Test C: The Interior Courtesy Lamp(s) Are Inoperative
Refer to Wiring Diagram Set 89, Interior Lamps for schematic and connector information. Diagrams By Number
Normal Operation
Power is supplied to the interior courtesy lamps and cargo lamp through the Smart Junction Box (SJB) fuse 9 (15A). Based on the input status, the SJB supplies voltage to the interior courtesy lamps through circuit VLN33 (GY/VT). Ground for the courtesy lamps is supplied through circuits GD133 (BK) and GD149 (BK/GY).
B2A35-B106F:
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Interior lamp
- Body builder equipment
- SJB
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.
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C1 CHECK THE OPERATION OF ALL THE INTERIOR COURTESY LAMPS
- Ignition OFF.
- Rotate the instrument panel dimmer switch to the DOME LAMP position and observe the interior courtesy lamps.
- Are all the interior courtesy lamps inoperative?
Yes
VERIFY the SJB fuse 9 (15A) is OK.
If OK:
For stripped chassis vehicles, GO to C4.
For all other vehicles that have a single interior courtesy lamp, GO to C5.
For vehicles that have multiple interior courtesy lamps, GO to C7.
If not OK, 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. TEST the system for normal operation.
No
GO to C2.
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C2 CHECK FOR VOLTAGE TO THE INTERIOR LAMP
- Rotate the instrument panel dimmer switch out of the DOME LAMP position.
- Disconnect: Inoperative Interior Lamp.
- Rotate the instrument panel dimmer switch to the DOME LAMP position.
- Measure the voltage between the inoperative interior lamp, harness side and ground as follows:
Vehicles With Rear Headliner:
Vehicles Without Rear Headliner (Except Cutaway):
Cutaway Chassis Vehicles:
- Is the voltage greater than 10 volts?
Yes
For the body builder connector, the vehicle is operating correctly. REFER to the body builder information to continue diagnosis.
For any other lamp, GO to C3.
No
REPAIR circuit VLN33 (GY/VT) for an open. TEST the system for normal operation.
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C3 CHECK FOR VOLTAGE TO THE INTERIOR LAMP USING THE CONNECTOR GROUND
- Measure the voltage between the suspect interior lamp pins, harness side as follows:
Vehicles With Rear Headliner:
Vehicles Without Rear Headliner (Except Cutaway):
Cutaway Chassis Vehicles:
- Is the voltage greater than 10 volts?
Yes
INSTALL a new interior lamp for the lamp in question. REFER to Interior Lamp Service and Repair. TEST the system for normal operation.
No
REPAIR the ground circuit in question for an open. TEST the system for normal operation.
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C4 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB DataLogger.
- Monitor the SJB instrument panel dimmer switch PID (DOMELM_SW) while rotating the instrument panel dimmer switch into and then out of the DOME LAMP position.
- Does the PID agree with the instrument panel dimmer switch position?
Yes
GO to C7.
No
Go To Pinpoint Test B. Pinpoint Test B: The Courtesy Lamps Do Not Turn On From The Instrument Panel Dimmer Switch
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C5 CHECK FOR VOLTAGE TO THE FRONT INTERIOR LAMP
- Ignition OFF.
- Disconnect: Front Interior Lamp C929.
- Rotate the instrument panel dimmer switch to the DOME LAMP position.
- Measure the voltage between the front interior lamp C929-1, circuit VLN33 (GY/VT), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to C6.
No
GO to C7.
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C6 CHECK FOR VOLTAGE TO THE FRONT INTERIOR LAMP USING THE CONNECTOR GROUND
- Measure the voltage between the front interior lamp C929-1, circuit VLN33 (GY/VT), harness side and the front interior lamp C929-2, circuit GD133 (BK), harness side
- Is the voltage greater than 10 volts?
Yes
INSTALL a new interior lamp for the lamp in question. REFER to Interior Lamp Service and Repair. TEST the system for normal operation.
No
REPAIR circuit GD133 (BK) for an open. TEST the system for normal operation.
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C7 BYPASS THE SJB
- Rotate the instrument panel dimmer switch out of the DOME LAMP position.
- Connect: Interior Lamp.
- Disconnect: SJB 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. TEST the system for normal operation.
- Connect a fused jumper wire between the SJB C2280a-9, circuit VLN33 (GY/VT), harness side and battery positive.
- Do the courtesy lamps illuminate?
Yes
REMOVE the jumper wire. GO to C8.
No
REMOVE the jumper wire. REPAIR circuit VLN33 (GY/VT) for an open. CLEAR the DTCs. REPEAT the self-test.
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C8 CHECK FOR CORRECT SJB OPERATION
- Disconnect all the SJB connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB 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. 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. CLEAR the DTCs. REPEAT the self-test.
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