Pinpoint Test A: All Dimmable Illumination Is Inoperative

Instrument Cluster and Panel Illumination

Pinpoint Tests

Pinpoint Test A: All Dimmable Illumination Is Inoperative

Refer to Wiring Diagram Set 71, Cluster and Panel Illumination for schematic and connector information. Diagrams By Number

Normal Operation

The Smart Junction Box (SJB) monitors the input from the instrument panel dimmer switch by sending a voltage signal to the instrument panel dimmer switch. The return signal is sent back to the SJB. Based on the signal, the SJB sends a pulse-width modulated voltage signal to the dimmable illumination sources and a network message to indicate the backlighting brightness level to the Instrument Cluster (IC) and the Audio Control Module (ACM).

- DTC B2132 (Dimmer Switch Circuit Short to Gnd) - a continuous and on-demand DTC that may set when the SJB detects a short to ground on the dimmer switch input circuit.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- Instrument panel dimmer switch
- SJB



PINPOINT TEST A: ALL DIMMABLE ILLUMINATION IS INOPERATIVE

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Make sure the light sensor is covered (to simulate darkness) for all tests.

-------------------------------------------------
A1 CHECK THE INSTRUMENT PANEL DIMMER SWITCH


- Ignition OFF.
- Disconnect: Instrument Panel Dimmer Switch C2298.
- Carry out the instrument panel dimmer switch component test.

- Is the instrument panel dimmer switch OK?

Yes
GO to A2.

No
INSTALL a new instrument panel dimmer switch. REFER to Instrument Panel Dimmer Switch Service and Repair. TEST the system for normal operation.

-------------------------------------------------
A2 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT CIRCUIT FOR A SHORT TO GROUND


- Disconnect: SJB C2280d.
- Measure the resistance between the SJB C2280d-18, circuit CLN27 (WH/BN), harness side and ground.




- Is the resistance greater than 10,000 ohms?

Yes
GO to A3.

No
REPAIR circuit CLN27 (WH/BN) for a short to ground. TEST the system for normal operation.

-------------------------------------------------
A3 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. REFER to Body Control Systems. 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.

-------------------------------------------------