Pinpoint Test B: The Instrument Panel Illumination Does Not Dim

WARNING: This page is about a different car, the 2009 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.

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

B1 MONITOR THE INSTRUMENT PANEL ILLUMINATION OPERATION
- With the parking lamps on, rotate the dimmer switch from maximum brightness to minimum brightness.
- Monitor all instrument panel illumination sources for correct operation.
- Do all the dimmable instrument panel illumination sources dim correctly?
1. YES : The system is OK.
2. NO : If only the instrument cluster (IC) does not dim, INSTALL a new IC. REFER to INSTRUMENT CLUSTER (IC), MESSAGE CENTER, AND WARNING CHIMES article. TEST the system for normal operation.
  If only the audio control module (ACM) does not dim, REMOVE the ACM. REFER to INFORMATION AND ENTERTAINMENT SYSTEMS article. SEND it to an authorized repair facility. TEST the system for normal operation after the repair.
  
  For all others, go to B2.
B2 CHECK THE SJB INSTRUMENT PANEL DIMMER SWITCH PIDs
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic tool: SJB DataLogger
- Turn the parking lamps on.
- Monitor the SJB PID (PANELINT) while rotating the instrument panel dimmer switch from the lowest setting to the highest setting.
- Do the SJB instrument panel dimmer switch PIDs agree with the instrument panel dimmer switch position?
1. YES : Go to B7.
2. NO : Go to B3.
B3 CHECK THE INSTRUMENT PANEL DIMMER SWITCH OPERATION
- Disconnect: Instrument Panel Dimmer Switch C2298
- Carry out the instrument panel dimmer switch component test. Refer to COMPONENT TESTING.
- Does the instrument panel dimmer switch pass the component test?
1. YES : Go to B4.
2. NO : INSTALL a new instrument panel dimmer switch. REFER to EXTERIOR LIGHTING article. CLEAR the DTCs. REPEAT the self-test.

B4 CHECK CIRCUITS 1035 (OG/RD), 1036 (BN/WH) AND 1405 (LB/BK) FOR A SHORT TO VOLTAGE

Key in OFF position.
Disconnect: SJB C2280d

Measure the voltage between the SJB, harness side and ground as follows:

Connector-Pin	Circuit
C2280b-43	1035 (OG/RD)
C2280b-32	1036 (BN/WH)
C2280b-1	1405 (LB/BK)

Is any voltage indicated?

YES : REPAIR the circuit. TEST the system for normal operation.
NO : Go to B5.

B5 CHECK CIRCUITS 1035 (OG/RD), 1036 (BN/WH) AND 1405 (LB/BK) FOR A SHORT TO GROUND

Measure the resistance between the SJB/GEM, harness side and ground as follows:

Connector-Pin	Circuit
C2280b-43	1035 (OG/RD)
C2280b-32	1036 (BN/WH)
C2280b-1	1405 (LB/BK)

Is the resistance greater than 10,000 ohms?

YES : Go to B6.
NO : REPAIR the circuit. TEST the system for normal operation.

B6 CHECK CIRCUITS 1035 (OG/RD), 1036 (BN/WH) AND 1405 (LB/BK) FOR AN OPEN

Measure the resistance between the SJB, harness side and the instrument panel dimmer switch, harness side as follows:

Connector-Pin	Circuit	Connector-Pin	Circuit
C2280b-43	1035 (OG/RD)	C2298-6	1035 (OG/RD)
C2280b-32	1036 (BN/WH)	C2298-1	1036 (BN/WH)
C2280b-1	1405 (LB/BK)	C2298-4	1405 (LB/BK)

Is the resistance less than 5 ohms?

YES : Go to B7.
NO : REPAIR the circuit. TEST the system for normal operation.

B7 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?
1. YES : INSTALL a new SJB. REFER to MULTIFUNCTION ELECTRONIC MODULES article. TEST the system for normal operation.
2. 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.