The Air Conditioning System Diagnostics; Air Conditioning Diagnostics; Cable Connections To The A/Ccm - Aston Martin DB7 Workshop Manual

Air Conditioning
Air-Conditioning 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
Cable Setup
Figure 1. PDU 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.
May 1996
8-65