MANUAL AIR CONDITIONER CONTROL SYSTEM

Block Diagram

• The climate control unit sends an A/C signal to the PCM via the PJB and instrument cluster based on signals sent from the A/C switch, fan switch and evaporator temperature sensor.

• The PCM sends operating signals to the A/C relay and IAC valve based on A/C signal and vehicle signal.

Outline of Control System

• Manual air conditioner A/C compressor control.

A/C Compressor Control

• The climate control unit sends an A/C signal to the PCM via the PJB and instrument cluster based on signals sent from the A/C switch, fan switch and evaporator temperature sensor.

• The PCM controls the A/C relay and IAC valve based on the input signal from the climate control unit and refrigerant pressure switch.

A/C signal on/off control

• The climate control unit turns the A/C signal (magnetic clutch) on and off based on the temperature of the air passing through the evaporator when the A/C and fan switches are on. This keeps the evaporator surface temperature within the specified range, preventing the evaporator from freezing while the fan switch and A/C switch are turned on.