Dimmed Illumination Test

Dimmed Illumination Test

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) .


Circuit/System Description

The infotainment unit is fully illuminated. The infotainment unit receives the illumination control signal from the hardwired illumination input on the connector. The actual dimming value is received from the BCM via GMLAN. The infotainment unit illumination test is performed using a scan tool, and controls the fascia illumination directly to verify correct operation.


Diagnostic Aids

* This diagnostic is for the infotainment unit illumination feature.
* Before diagnosis of the illumination feature, make sure the primary controls of the associated components are functioning properly.



Reference Information

Scan Tool Reference

Control Module References (Programming and Relearning)


Component Testing

Important: It is recommended that component testing is performed before circuit testing when diagnosing infotainment unit functions.



1. Turn the park lamps on.
2. Connect the scan tool to the DLC and select Infotainment
System / Audio System / Actuator Test / Display / Illumination .
3. Ignition On, infotainment unit On.
4. Using the Increase soft key on the scan tool, increase the illumination level to maximum.
5. Check the display illumination is even with no dark patches, and the fascia control buttons are illuminated.
6. To decrease the infotainment unit illumination, press the Decrease soft key on the scan tool. Check the fascia illumination decreases accordingly.
7. Press the Quit soft key to exit the test.

• If the illumination function does not operate correctly, replace the infotainment unit.




Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) .


Radio Replacement (Service and Repair)