Fault Code 21

Fault Code 21

Solar Sensor
- Sensor, harness or Air Conditioning Control Module (A/CCM) open circuit.
- Sensor, harness or A/CCM short circuit to ground.

The sensor provides a linear output response signal to pin 35 (16-way connector) A/CCM; the output ranges from 0 to 5 volts, the voltage will drop as light intensity increases.

A resistance check can be carried out on the sensor and should conform with the figures below:

With no light on the sensor, the resistance should read approximately 15 K Ohm.

With increasing light intensity, the resistance should decrease from 15 K Ohm.

Inspect the sensor harness for open circuit or short circuit to ground. repair as necessary.

If the sensor and harness appear correct, suspect the A/CCM.