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 sensor
- ambient temperature sensor
- sunload sensor
- vehicle speed sensor
- engine coolant temperature sensor

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

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Part 2 Of 2:

System Response
a If engine coolant temperature fails to reach 50°C (122°F) after 3-1/2 minutes of operation, the heater blower motor speed will increase and the windshield defroster door will shift from defrost position to floor position.
b The A/C system is enabled by the EATC control assembly, but final control of the A/C compressor clutch is determined by the Powertrain Control Module (PCM) through the use of a normally open clutch control relay. The A/C clutch can be shut off (or kept off) for several seconds at engine start-up, during high engine speeds, during low engine idle conditions (approximately 200 rpm below idle specs) and when the engine coolant temperature sensor reading exceeds approximately 120°C (248°F).