Wiper and Washer Systems: Description and Operation

Wash And Wipe System And Headlight Cleaning System

Operating principle
The windscreen wipers, the windscreen washer pump and the pump for the headlight cleaning system are controlled by the Junction Box Electronics (JBE) control unit.
The wash/wipe switch is connected to the steering column switch cluster (SZL). The switch statuses are sent via F-CAN to the DSC control unit and from the DSC control unit via PT-CAN to the JBE control unit.
In the automatic mode, the rain-driving light-sensor (RLS) registers the rain intensity. It sends the data on the LIN bus to the roof function centre (FZD). The FZD then sends the rain intensity on the K-CAN to the JBE.
To prevent the washer jets of the car wash from freezing, there is a washer jet heating. The JBE controls this heater depending on the ambient temperature. The JBE receives the ambient temperature from the instrument panel across the K-CAN. The washer jet heating is activated together with the heater for the exterior mirrors.

Relays in the power distribution box
The following relays for the wash and wipe system are installed in the front power distribution box:
- Wiper relays K36 (can be replaced individually)
- Changeover relays, wiper stage 1/2 K37 (cannot be replaced individually)
- Relays for rear wiper K91 (can be replaced individually)
- Relays for headlight cleaning system K6 (can be replaced individually up to production date 03/07)