740 L4-2.3L SOHC VIN 88 B230F (1985)
A/C Signal: Description and Operation
A/C Pressure Sensor
Used by the ignition ECU:
When the A/C compressor is in operation, an electrical signal is sent from the pressure sensor (located on the receiver/dryer at passenger side fire-wall)
to the ECU.
When the A/C system pressure is low, the pressure sensor will come on (A/C compressor turns on) and send a signal to the ECU. If the pressure is
sufficient for the A/C system to operate without the compressor, the pressure sensor will stay off and no signal is sent to the ECU.