Status Lights Display
WARNING: This page is about a different car, the 1990 Cadillac Fleetwood and 1990 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
While in self-diagnostics, the mode indicators on the ECC panel automatically indicate system operating modes, the different modes of operation being indicated by illuminated or non-illuminated status lights. Following is a description of the various status lights and their meaning in relation to system operations.
- AUTO Status Indicator This indicator is turned on whenever the ECM is operating in closed-loop fuel control. See Fig 1 . This light should come on after the coolant and oxygen sensors have reached normal operating temperatures.
- ECON Status Indicator This indicator is used for the oxygen sensor signal. The indicator is on for rich exhaust condition. See Fig 1 . The indicator should toggle on and off with a warm engine and steady throttle.
- OFF Status Indicator This indicator is turned on when the ECM senses the throttle switch of the Idle Speed Control (ISC) motor is closed. See Fig 1 . This light should be off when engine RPM is above idle.
- FRONT DEFOG Status Indicator This indicator is used for the Viscous Converter Clutch (VCC). See Fig 1 . The light only indicates whether the ECM is commanding the VCC solenoid to energize or de-energize. Actual operation depends on the integrity of the VCC system.
- REAR DEFOG Status Indicator This indicator is used for the 4th gear pressure switch. See Fig 1 . This light should only be on in 4th gear.
- OUTSIDE TEMP Status Indicator
This indicator is turned on when the BCM is requesting the A/C compressor clutch to engage. See Fig 1
. This light only indicates whether the clutch is enabled or disabled by the BCM. Actual operation depends on the integrity of the system.NOTE: Extended clutch interval is inhibited during diagnostic mode.
- AUTO FAN Status Indicator
This status indicator is turned on when the signal from the coolant fan control relays indicates the fans are commanded
- See Fig 1 . This light should be off when the fans are commanded off.
- HI FAN Status Indicator This indicator is turned on when the BCM is commanding the up-down mode door to divert airflow down to the heater outlet. See Fig 1 . This light will be off when the ECC system is in the normal purge modes.
- LO FAN Status Indicator This indicator is turned on when the BCM is commanding the A/C defrost mode door to divert airflow to the A/C outlets as in the A/C or normal purge modes. See Fig 1 . This light will be off when the ECC system is in the heater defrost and cold purge modes.
- °F (Fahrenheit) Status Indicator This indicator is turned on when the BCM senses the refrigerant low pressure switch or circuit is open. See Fig 1 . This light will come on when the ambient temperature falls below approximately -5°F due to the pressure temperature relationship of R-12. This light should remain off if the refrigerant system is fully charged and being properly controlled.
- °C (Centigrade) Status Light This indicator is turned on when the BCM is commanding the heater water valve to block coolant flow through the heater core. See Fig 1 . This light should remain off except when the air mix door is being commanded to the maximum A/C position (0%).