The rain sensor activates the wipers automatically when it detects rain on the windscreen, and is fitted to the top of the windscreen at the front of the vehicle.
- The rain sensor is a device that senses the amount of rain falling on the windscreen and signals this to the control module/body control module (BCM).
- The rain sensor is an optical device that contains an LED (light-emitting diode) and photodiode.
- The photodiode continuously senses the amount of light reflected back by the windscreen’s surface.
- When rain falls onto the windscreen it refracts the light beam to the sides, blocking the light from reaching the photodiode.
- The drop in the amount of light being reflected back to the photodiode causes a change in resistance, which is interpreted by the control module/BCM as rain on the windscreen.
Automatic mode operation
On detecting rain, the control module signals the body control module (BCM), which then signals a high or low speed setting to energise the appropriate relay in the fuse/relay box and operate the intermittent wiper motor at the chosen speed.
The amount of time between automatic wiper operations can be changed between three settings via the menu settings on the instrument panel centre stack display screen:
- Fast
- Normal
- Slow
Overriding automatic mode
The Automatic wiping operation can be interrupted by moving the wiper stalk to other positions and will resume operation when the stalk is returned to the ‘AUTO’ position.
Vehicle security
If the automatic wipers are in operation when the vehicle is locked and armed the wipers will stop operating once the vehicle is locked.
