Pinpoint Test C: The Heating Ventilation Air Conditioning (HVAC) Illumination Is Inoperative
WARNING: This page is about a different car, the 2010 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
Normal Operation
The lighting control module (LCM) communicates the requested level of backlighting intensity to the heating ventilation air conditioning (HVAC) module through the standard corporate protocol (SCP) network.
This pinpoint test is intended to diagnose the following:
- HVAC module
- LCM
PINPOINT TEST C: THE HEATING VENTILATION AIR CONDITIONING (HVAC) ILLUMINATION IS INOPERATIVE
- C1 CHECK THE HVAC MODULE FOR CORRECT ILLUMINATION
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic tool: Active Commands
- Using the scan tool, command the HVAC display dimming to full daytime brightness.
- Does the HVAC illuminate correctly?
- C2 CHECK FOR CORRECT HVAC MODULE OPERATION
- Key in OFF position.
- Disconnect all the HVAC module connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the HVAC module 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 HVAC module. REFER to CLIMATE CONTROL 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.
- C3 CHECK FOR CORRECT LCM OPERATION
- Key in OFF position.
- Disconnect all the LCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the LCM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern is still present?
- YES : INSTALL a new LCM. REFER to MULTIFUNCTION ELECTRONIC MODULES 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.