Status Light Displays(BCM)

While in diagnostic service mode, the lights on the Climate Control Panel (CCP) function buttons indicate status of various operating modes. The meaning of each word or symbol on the ECC panel will change depending on whether the BCM or ECM system level is selected. The different modes of operation are indicated by the light being either on or off. Lights and the mode they represent are as follows:

1. "OFF" Button
   
   This light is illuminated whenever the BCM is commanding recirculation.
2. "AUTO" Button
   
   This light is illuminated whenever the up-down air control switch is in the "NORMAL" position.
3. "FRONT DEFOG"
   
   This light is illuminated whenever ECM allows A/C clutch engagement through the A/C clutch relay. This light should be on if the BCM is in control of the A/C clutch. The light will be off if the ECM is commanding A/C clutch disengagement.
4. "REAR DEFOG"
   
   This light indicates 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 about -5°F (-21°C), the light will come on due to the pressure-temperature relationship of R-12.
5. "LOW FAN"
   
   This status indicator is turned on whenever the BCM is commanding the A/C-DEF mode door to divert air flow to the A/C outlets (as is A/C or normal purge modes).This light will be off whenever the ECC system is in the heater, intermediate, defrost and cold purge modes.
6. "HI FAN"
   
   This status indicator is turned on whenever the BCM is commanding the HVAC programmer to not supply vacuum to the park brake release motor (park brake remains applied). The light is off when the BCM commands the park brake to be released.