Backlight Dimming RX Failure (Active)

Tests 1 - 2:

SYMPTOM
BACKLIGHT DIMMING RX FAILURE (ACTIVE)

WHEN MONITORED
With the ignition ON.

SET CONDITION
If the A/C - Heater Control Module does not receive the dimming function message from the Instrument Cluster for more than 5 seconds, then the A/C - Heater Control Module backlighting will default to full brightness and the DTC will set.

POSSIBLE CAUSES
- Verify instrument cluster dimming is operational
- A/C - heater control module
- Instrument cluster - no dim message to A/C - heater control module