Perform Function Test For Rain/Light Sensor - Ar82.00-S-0020-01S

Model 906 with code JA5 (Light and rain sensor) 

Shown on model 639 

1. Switch on ignition.

   Leave ignition switched on for min. 5 s.

2. Switch off ignition.

   Leave ignition switched off for min. 5 s.

   Measuring field of the windshield is calibrated in the humidity sensor/light sensor/rain sensor (B38/2) and the measurement values stored.

   Courtesy of MERCEDES-BENZ USA

3. Turn on ignition.
4. Move combination switch to intermittent operation "I".
5. Wet windshield with a little water in vicinity of humidity sensor/light sensor/rain sensor (B38/2).
6. Move rotary light switch to "AUTO".
7. Cover humidity sensor/light sensor/rain sensor (B38/2).

   Exterior lights must switch on automatically.

   Windshield wiper must switch itself on.