Status Lights

BCM Diagnostic Flow Chart (Part 2 of 2):

While in the BCM system level in the diagnostic service mode, the mode indicators on the Climate Control Panel (CCP) of the CCDIC are used to indicate the status of certain operating modes. The different modes of operation are indicated by the status light being illuminated or turned off.

A brief summary of each status light is provided below:

1. The "OFF" status indicator is illuminated whenever the BCM commands the air inlet valve to the recirculation position.

2. The "AUTO" status indicator is illuminated whenever the up-down air control switch on the CCP is in the "Normal" position.

3. The "FRONT DEFOG" status indicator is illuminated whenever the BCM is requesting the PCM/ECM to engage the compressor clutch. The light does not indicate whether the clutch is enabled or disabled by the PCM/ECM, and actual operation depends on the PCM/ECM and the integrity of the compressor clutch system.

4. The "REAR DEFOG" status indicator is illuminated whenever the BCM senses that the low refrigerant pressure switch is open. The light should remain off if the refrigerant system is fully charged and being properly controlled. However, when the ambient temperature drops below approximately -5°F (-21°C), the light will come on due to the pressure temperature relationship of refrigerant R-12.

5. The "LO FAN" status indicator is illuminated whenever the BCM is commanding the A/C-DEF mode door to divert air flow to the A/C outlets, as in the A/C or normal purge modes.

6. The "HI FAN" status indicator is illuminated whenever the BCM is commanding the HVAC programmer to not supply vacuum to the park brake release motor (park brake remains applied). This light will be off whenever the BCM commands the park brake to be released.