Diesel Data: Automotive Repair

Pinpoint Test A: The Courtesy Lamps Are Inoperative




Interior Lighting

Pinpoint Tests

Pinpoint Test A: The Courtesy Lamps Are Inoperative

Refer to Wiring Diagram Set 89, Interior Lamps for schematic and connector information. Diagrams By Number

Normal Operation

The Smart Junction Box (SJB) fuse 9 (15A) supplies voltage to the courtesy lamps. When the SJB receives a request for the courtesy lamps, the SJB energizes the solid-state relay supplying voltage to the courtesy lamps on circuit VLN33 (GY/VT). Ground for the courtesy lamps is supplied through circuit GD133 (BK).

- DTC B2A35 (Interior Lighting Output Circuit Open) - an on-demand DTC that sets when the SJB detects an open from the interior lighting circuit.
- DTC B2A36 (Interior Lighting Output Circuit Short to Ground) - a continuous and on-demand DTC that sets when the SJB detects a short to ground from the interior lighting circuit.

This pinpoint test is intended to diagnose the following:

- Fuse
- Wiring, terminals or connectors
- Interior lamp
- SJB



PINPOINT TEST A: THE COURTESY LAMPS 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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A1 CHECK THE OPERATION OF THE DEMAND LIGHTING


- Operate the demand lighting function on the interior lamp.
- Does the interior lamp illuminate?

Yes
GO to A2.

No
REPAIR circuit GD133 (BK) for an open. CLEAR the DTCs. REPEAT the self-test.

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A2 CHECK CIRCUIT VLN33 (GY/VT) FOR VOLTAGE


- Ignition OFF.
- Disconnect: Interior Lamp C931.
- Open any door.
- Measure the voltage between the interior lamp C931-2, circuit VLN33 (GY/VT), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
INSTALL a new interior lamp. REFER to Interior Lamp Service and Repair.

No
VERIFY the SJB fuse 9 (15A) is OK. If OK, GO to A3. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.

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A3 CHECK CIRCUIT VLN33 (GY/VT) FOR AN OPEN


- Connect: Interior Lamp C931.
- Ignition OFF.
- Disconnect: SJB C2280a.
- 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 A4.

No
REMOVE the jumper wire. REPAIR the circuit. RUN the on-demand self-test (required to clear certain DTCs). CORRECT any unresolved DTCs. CLEAR all DTCs. TEST the system for normal operation.

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A4 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. RUN the on-demand self-test (required to clear certain DTCs). CORRECT any unresolved DTCs. CLEAR all DTCs. TEST the system for normal operation.

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