Pinpoint Test B: All DIMMABLE Illumination Does Not Dim
NOTE:
Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE:
Calibrate the instrument panel dimmer switch by rotating the dimmer switch from the full dim position to the dome on position before continuing diagnostics.
- B1 CHECK THE EXTERIOR LIGHTING OPERATION
- Place the headlamp switch in each of its positions while observing the exterior lamps.
- Do the exterior lamps operate correctly?
- YES: GO to B2 .
- NO: REFER to EXTERIOR LIGHTING SYSTEM article.
- B2 CHECK THE INSTRUMENT PANEL DIMMER SWITCH
- Ignition OFF.
- Disconnect: Instrument Panel Dimmer Switch C2065.
- Carry out the component test for the instrument panel dimmer switch.
Refer to ILLUMINATION DIMMER SWITCH (14A464) for component testing.
- Is the instrument panel dimmer switch OK?
- YES: GO to B3 .
- NO: INSTALL a new instrument panel dimmer switch. REFER to INSTRUMENT PANEL DIMMER SWITCH in this service information. TEST the system for normal operation.
- B3 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: SJB C2280b.
- Ignition ON.
- Measure the voltage between the instrument panel dimmer switch C2065-6, circuit VLN18 (BU/WH), harness side and ground.
- Is any voltage present?
- YES: REPAIR circuit VLN18 (BU/WH) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
- NO: GO to B4 .
- B4 CHECK THE INSTRUMENT PANEL DIMMER SWITCH RETURN CIRCUIT FOR A SHORT TO VOLTAGE
- Measure the voltage between the instrument panel dimmer switch C2065-4, circuit CLN04 (BU/BN), harness side and ground.
- Is any voltage present?
- YES: REPAIR circuit CLN04 (BU/BN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
- NO: GO to B5 .
- B5 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the instrument panel dimmer switch C2065-6, circuit VLN18 (BU/WH), harness side and ground.
- Is the resistance greater than 10,000 ohms?
- YES: GO to B6 .
- NO: REPAIR circuit VLN18 (BU/WH) for a short to ground. CLEAR the DTCs. REPEAT the self-test.
- B6 CHECK THE INSTRUMENT PANEL DIMMER SWITCH RETURN CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between the instrument panel dimmer switch C2065-4, circuit CLN04 (BU/BN), harness side and ground.
- Is the resistance greater than 10,000 ohms?
- YES: GO to B7 .
- No: REPAIR circuit CLN04 (BU/BN) for a short to ground. CLEAR the DTCs. REPEAT the self-test.
- B7 CHECK THE INSTRUMENT PANEL DIMMER SWITCH INPUT CIRCUIT FOR AN OPEN
- Measure the resistance between the instrument panel dimmer switch C2065-6, circuit VLN18 (BU/WH), harness side and the SJB C2280b-34, circuit VLN18 (BU/WH), harness side.
- Is the resistance less than 5 ohms?
- YES: GO to B8 .
- NO: REPAIR circuit VLN18 (BU/WH) for an open. CLEAR the DTCs. REPEAT the self-test.
- B8 CHECK THE INSTRUMENT PANEL DIMMER SWITCH RETURN CIRCUIT FOR AN OPEN
- Measure the resistance between the instrument panel dimmer switch C2065-4, circuit CLN04 (BU/BN), harness side and the SJB C2280b-33, circuit CLN04 (BU/BN), harness side.
- Is the resistance less than 5 ohms?
- YES: GO to B9 .
- NO: REPAIR circuit CLN04 (BU/BN) for an open. CLEAR the DTCs. REPEAT the self-test.
- B9 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 MULTIFUNCTION ELECTRONIC MODULE article. 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.