Control Module HVAC: Description and Operation

DATC Module
The DATC module:
- is located in the instrument panel.
- has a vacuum fluorescent display for displaying set temperature, function and Diagnostic Trouble Codes (DTCs).
- utilizes an On-Board Diagnostic (OBD) feature to supply the technician with diagnostic trouble codes (DTCs). These DTCs direct the technician to the inoperative component.

Blower Motor Speed Control
The blower speed control:
- is located on the heater core and evaporator core housing near the blower motor.
- converts low power signals from the DATC module to a high current, variable ground feed for the blower motor.
- varies the blower motor speed and is controlled by the DATC module software.
- has a delay function to provide a gradual increase or decrease in blower motor speed under all conditions.
- controls the integral high blower speed relay which is engaged when maximum fan speed is selected.