Backlight Dimming RX Failure (Active)

BACKLIGHT DIMMING RX FAILURE (ACTIVE)

For a complete wiring diagram refer to the Wiring Information Electrical Diagrams

- When Monitored:
With the ignition on.

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





1. DIMMING MESSAGE NOT SEEN AT RATE EXPECTED

NOTE: Make sure that the Panel Dimmer switch is not in set in Funeral Mode.

1. Turn the ignition on.
2. Turn the Blower control to low speed.
3. Press the A/C switch on.
4. Press the EBL switch on.
5. Watch the A/C and EBL status indicators on the A/C-Heater Control Module while turning the Headlamp switch on and then off.

Did the status indicators dim when the Headlamp switch was turned on?

Yes

- No problem found at this time.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Go To 2

2. A/C HEATER CONTROL MODULE
1. Turn the ignition on.
2. With the scan tool in Monitor Display, PCI Bus Messages, look for the VF DIM Msg Present.

Does the scan tool display: VF DIM Msg present: Yes?

Yes

- Replace the A/C - Heater Control Module.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Replace the Body Control Module.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test.