Electronic Climate Control Module

Control Components:

With the use of a microcontroller, the Electronic Automatic Temperature Control (EATC) module analyzes input from the following major sources:
- temperature, function and blower selection (made by the vehicle occupants)
- in-vehicle temperature
- ambient temperature
- sunload
- vehicle speed
- engine coolant temperature

Using these inputs, the microcontroller determines the correct conditions for the following outputs:
- A/C clutch engagement
- blower speed
- air temperature blend door position
- heater air damper door position
- windshield defroster door position
- air inlet duct door position

EATC System Response Chart Part 1 Of 2:

EATC System Response Chart Part 2 Of 2:

System Response
a The A/C clutch circuit is energized by the EATC module but the final control of clutch operation is determined by the powertrain control module. The A/C clutch can be shut off (or kept off) for several seconds at engine start-up, during high engine speeds, during acceleration, during low engine idle conditions (approximately 200 rpm below idle specs) and when the engine coolant temperature exceeds approximately 120°C (248°F).

b If the engine coolant temperature fails to reach 50°C (122°F) after 3 1/2 minutes of operation, the blower motor speed will increase and the windshield defroster door will shift from the DEFROST position to the FLOOR position.