A/C Pressure Sensor

A/C System Controls Circuit Diagram:

Purpose:
The PCM uses the pressure sensor to turn "ON" the engine cooling fans. It also can prevent compressor damage during periods of excessively high head pressure.

Operation:
A 5 volt reference is supplied to the sensor and returned to the PCM on the signal line. As A/C pressure increases or decreases, the resistance of the sensor changes and varies the amount of signal returning to the PCM. The computer monitors the sensor for control of the A/C compressor and engine cooling fans. If the sensor signal indicates A/C system operation, the cooling fans are enabled. The control module also compares information from the pressure sensor with the desired status of the compressor clutch, for self diagnostics of the A/C system. When the compressor is commanded "ON", the computer looks for an increase in pressure indicated by the sensor signal. If the sensor signal indicates excessively high pressure in the A/C system, the compressor clutch will be disabled to prevent system damage.

Location:
The A/C pressure sensor is installed in the the A/C system high pressure line at the right rear of the engine compartment.