Checking the component

Check the sun sensor signal by varying the intensity of the light that it detects.

Cover the sun sensor with your hand to obtain the minimum signal, approximately 0.5 volts.

Then direct a strong light source (for example a flashlight) at the sun sensor from close range to increase the signal.

HINT: If the signal from the sun sensor is constantly above 4.85 volts, there is either an open-circuit in the cable or the sun sensor is defective. 

Fig 2: Identifying VCT2000 Diagnostic Tool Symbol In VIDA

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 3: Identifying Sun Sensor

Courtesy of VOLVO CARS OF NORTH AMERICA.

Refer to Checking the wiring