Automatic Climate Controls

DESCRIPTION

Control Assembly

The Heater And A/C Control Assembly controls the blower speed, Air Mix Valve position, Mode Valve position (via the Electronic Climate Control (ECC) programmer), and A/C Compressor Clutch operation (via the Engine Control Module (ECM)).

The input signals from the in-car Temperature Sensor, Ambient Temperature Sensor, selected temperature setting, blower speed and Air Mix Valve position determine the Heater And A/C Control Assembly output signals.

Programmer

The ECC Programmer controls the operation of three vacuum actuators based on the output from the Heater and A/C Control Assembly. Each vacuum actuator controls the position of a valve which directs air flow through the plenum.

Control Module

The Blower Control Module receives a blower speed input signal from the Heater And A/C Control Assembly. The Blower Control Module amplifies the signal and applies it to the Blower Motor.

Engine Control Module

The Engine Control Module (ECM) will engage the A/C Compressor Clutch once it has received a request signal from the Heater And A/C Control Assembly and has increased idle speed to compensate for increased engine load. The ECM must also determine that a wide open throttle condition, high power steering load, or high coolant temperature condition does not exist before allowing the A/C Compressor Clutch operation.