Control Module HVAC: Description and Operation

General Description





At the heart of the air conditioning control module is a digital micro-processor which receives data signals from driver controlled switches. By comparing this data with the signals received from the various temperature sensors and the feedback devices, it calculates the output voltages needed to operate the blower motors at the required speed and the flap servo motors to the required positions. It also controls the compressor and the vacuum solenoids to acheive the temperature requirements selected for the vehicle.

Although the control module cannot be repaired in service, a complete set of test pins are accessible for testing the system. Great Care must be exercised when connecting the test equipment for the control module will be irreparably damaged should any of the test pins be momentary shorted together.