HVAC Parameters

HEATING, VENTILATION, AND AIR CONDITIONING (HVAC) PARAMETERS

NOTE:
These parameters indicate logic module commands to, and signals from, various actuators and sensors in the HVAC systems.


AIR CONDITIONING SWITCH

A/C SWITCH - XXX RANGE: ON - OFF

This discrete parameter on 1989 and later vehicles should be ON when the air conditioning switch is on and all other in-series switches are closed. It should be OFF when any sense switch in the air conditioning circuit is open.


AIR CONDITIONING CLUTCH

A/C CLUTCH RANGE: ON - OFF

This discrete parameter on some 1989 and later vehicles indicates that the logic module has energized the relay to engage the air conditioning compressor clutch. This parameter indicates that the logic module command has been given. It is not a feedback signal to indicate that the A/C clutch has actually engaged.


AIR CONDITIONING REQUEST SIGNAL

A/C REQUEST - XXX RANGE: ON - OFF

This discrete parameter on some 1991 and later vehicles indicates the status of the logic module command (SMEC or SBEC) to the air conditioning compressor. This is the actual computer command, not the switch position. A/C SWITCH indicates the position of the instrument panel switch.