Compressor lock sensor circuit

This sensor sends 1 pulse per engine revolution to the air conditioning amplifier. If the ratio of the compressor speed divided by the engine speed is smaller than a predetermined value, the air conditioning amplifier turns the compressor off, and the indicator blinks at approximately 1 second intervals.

1. Check air conditioning amplifier (lock signal)

1. 1
   Remove the air conditioning amplifier with its connectors still connected.
2. 2
   Check the waveform of the amplifier connector.

Ok: waveform is as shown in the illustration.

2. Inspect compressor lock sensor

1. 1
   Disconnect the b47 compressor lock sensor connector.
2. 2
   Measure the resistance of the sensor.

Standard resistance

3. Check wire harness (compressor lock sensor - air conditioning amplifier)

1. 1
   Disconnect the b47 compressor lock sensor connector.
2. 2
   Disconnect the e37 amplifier connector.
3. 3
   Measure the resistance of the wire harness side connectors.

Standard resistance