Rain/Light Sensor
On receiving a request for automatic windshield wiper operation, the CJB interprets LIN bus messages received from the rain sensor. The rain sensor provides LIN bus messages with values ranging from 0 to 7.
A signal value of 0 is interpreted by the CJB as the windshield is dry. A signal value from 1 to 6 is interpreted by the CJB as a small amount of water hitting the windshield. In this instance, the CJB initiates a slow wipe. A signal value of 7 is interpreted by the CJB as a large amount of water hitting the windshield. In this instance, the CJB initiates a fast wipe.
- The CJB will only change a fast wipe routine to a slow wipe routine if the rain sensor value is lower than 7.
- A = Clean and dry windshield; B = Wet and dirty windshield
| ITEM | DESCRIPTION |
|---|---|
| 1 | Windshield outer surface |
| 2 | Optical element |
| 3 | Transmitter diodes (100% light transmitted) |
| 4 | Rain sensor |
| 5 | Receiver diodes (100% light received) |
| 6 | Water droplets/film |
| 7 | Receiver diodes (less than 100% light received) |
| 8 | Lost light |
The rain/light sensor is located at the upper edge of the windshield, behind the interior rear view mirror. Contact between the rain sensor and windscreen is provided via a silicon pad which is compressed during the assembly process by two locking retaining clips either side of the sensor.
The rain/light sensor unit attaches to the windshield via two clips, which latch onto formed tags on the windshield bracket.
The sensor provides information to the CJB for the optimum wiper operation for the prevailing conditions to maintain the shield in a clear condition at all times. The rain/light sensor is an optical unit, which operates on an infrared waveband. The sensor uses the principle of the laws of reflection on interfacing surfaces between materials with differing refraction properties.
The rain/light sensor is connected to the CJB via a LIN bus. The sensor also receives a hardwired power and ground from the CJB. The 'auto' wipers are activated when the column stalk is moved to position 1 (first position from off in the upward direction). The sensitivity of the sensor can be adjusted by rotating the sensitivity collar on the wiper column stalk in the clockwise or counterclockwise direction. Clockwise rotation will decrease sensitivity, while counterclockwise adjustment will increase sensitivity. An increase in sensitivity adjustment results in a single wipe of the front wiper motor.
For additional information, refer to
Exterior Lighting (Description and Operation),
Exterior Lighting (Description and Operation),
Exterior Lighting (Description and Operation).