Status Lights

Status Lights:

While in the diagnostic service mode, the mode indicators on the ECC panel 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 "OUTSIDE TEMP" status indicator is illuminated whenever the BCM is requesting the A/C compressor clutch to engage. This light only indicates whether the clutch is enabled or disabled by the BCM. Actual operation depends on the integrity of the compressor clutch system. The BCM requests A/C clutch engagement based on information supplied by the ECC panel. A request is then sent from the BCM to the PCM/ECM which has direct control of the A/C compressor clutch relay.

2. The "AUTO FAN" status indicator is illuminated when the signal from the coolant fan control relays indicates that the fans are commanded "ON." This light should be "OFF" when the fans are commanded "OFF."

3. The "HI FAN" status indicator is illuminated whenever the BCM commands the up-down air mode door to divert air flow down to the heater outlet. This light will be "OFF" when the ECC system is in the "normal purge" modes.

4. 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. This light will be "OFF" when the ECC system is in the heater, defrost, and cold purge modes.

5. The "°F" status indicator is illuminated whenever the BCM senses that the low refrigerant pressure switch or circuit 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.

6. The "°C" status indicator is illuminated whenever the BCM is commanding the heater water valve to block coolant flow through the heater core. This light should remain "OFF" except when the air mix door is being commanded to the Max A/C position (0%).