Wiper Pressure Control Motor: Description and Operation

Windscreen Wiper Pressure Control (ZKE/ADV):

Functional Description:




General:

The windscreen wiper pressure control (ADV) is controlled and monitored by the general module (GM) of the ZKE II. Activation of the ADV module takes place in the relay module (PM).

Operating Principle:

The ADV system controls the contact pressure of the wiper arm on the

Driver's side dependent on the vehicle speed and on the active wipe and wash functions by way of a DC motor.

The wiper arm is in a relieved setting at terminal R OFF. The ADV Drive is set to stage 1 when the windscreen is washed with the vehicle stationary. The assignment of the vehicle speed and contact pressure are dependent on the current wipe and wash function. (See characteristic map ADV stages).

Integrated in the ADV motor is a cam switch which signals to the general module (GM) when the relevant contact pressure is reached. The switch switches ground to the general module (GM) for as long as the ADV motor operates. When the ADV motor reaches the next cam, the cam switch interrupts the ground connection and the motor stops.

Characteristic Map ADV Stages:




Anti-Blocking Function:

If the general module (GM) detects a fault in the ADV system, it activates an antiblocking function which switches off the ADV motor. The anti blocking function can be canceled by ignition OFF/ON.

Function Monitoring:

The general module (GM) uses the signals of the cam switch in the ADV motor for monitoring operation. If the signals are not received or it a ground is applied at the general module (GM) for too long, the general module considers this as a defect and the ADV motor is switched off by the antiblocking function (see defect code 22).

The 2 ADV relays in the ADV module are monitored via a diagnostic link. If a relay sticks, then the second relay is also switched on (for potential equalization) in order to stop the ADV motor. This function is canceled when the vehicle travels faster than 12 km/h or the wash feature is operated and the ADV relay is intact once again.

The potential equalization can also be activated by removing and installing the ADV module.

Attention: Potential equalization is also active when the ignition is switched off. This results in an excessively high close-circuit current consumption (battery discharge!).