The Air Conditioning System Diagnostics

The Air Conditioning System Diagnostics

The air-conditioning control module (A/CCM) is located at the right end of the air-conditioning unit.

A digital microprocessor within the A/CCM receives data signals from the operator controlled switches. Comparison of these signals with those returned from the system temperature sensor and feedback devices results in the appropriate voltage changes necessary to vary: blower motor speed, flap positions and system solenoids to respond to the drivers selected temperature demand.

The air from the two blower motors is passed through the evaporator matrix which, depending on the A/C mode selected, removes heat from the incoming air. Depending on the position of the two blend flaps, the cold air passes either directly into the vehicle outlet vents, or is passed through the heater matrix to be reheated and then passed to the vehicle outlet vents.

The amount of air passing through the heater matrix is infinitely variable depending on ambient temperature and the temperature selected within the vehicle.

Air Conditioning Diagnostics

Cable Connections to the A/CCM

1. Remove the right side underdash trim panel.
2. Connect the VBA (0024) to the vehicle battery
3. Connect the PDU to the VBA (0024).
4. Connect the VIA to the PDU using the VIA-PDU cable (0030).
5. Connect the AirCon DataLogger harness (0780) between the VIA Channel A and the Air-Conditioning Control Module on the vehicle.