BMW 7 Series: Functions

Wiping

The wiper/washer system is switched on and off with the wiper switch. The wiper switch is an integral part of the steering column switch cluster SZL.

Wiper Switch

The wiper switch on the steering column stalk does not lock in position. It always returns to its start position after every operation. The button for the rain/lights/solar/condensation sensor also returns to its starting position after every operation. The wiper-stage switch does lock in position.

The following functions are switched on with the wiper switch on the steering column stalk:

• Automatic wipe with rain/lights/solar/condensation sensor
• Continuous wipe, stage 1
• Continuous wipe, stage 2
• Flick wipe
• Wash windscreen

The signals from the wiper switch on the steering column stalk are sent from the steering column switch cluster via the FlexRay to the central gateway module. From the central gateway module, the signal is transmitted to the junction box electronics via the KCAN2. The junction box electronics evaluates the signals and actuates the wiper motor via the LIN bus. The junction box electronics also monitor the wipe function via the LIN bus. To do so, the junction box electronics cyclically request the status of the wiper motor.

Directions of movement

Fig. 81: Identifying Wiping And Wiper Switch Movement Directions

WIPER SWITCH MOVEMENT DIRECTIONS

   0.  Steering column stalk/start position of wiper-stage switch

1. Wiper stage 1
2. Wiper stage 2
3. Wiping while steering column stalk operated
4. Activates/deactivates the rain/lights/solar/condensation sensor
5. Washer fluid and windscreen wiper at same time
6. Increases the sensitivity of the rain/lights/solar/condensation sensor
7. Reduces the sensitivity of the rain/lights/solar/condensation sensor

Windscreen Wipe Function

The following functions are available for wiping the windscreen:

• Intermittent wipe in stages
• Automatic wipe
• Continuous wipe, stage 1
• Continuous wipe, stage 2
• Flick wipe.

Intermittent wipe

The interval can be set with the multi-stage switch. Four intermittent wipe stages are available. The time intervals depend on the set intermittent wipe stage and the vehicle speed. The junction box electronics calculate the time intervals and actuate the wiper motor accordingly.

Automatic wipe

The automatic wipe function can be activated by pressing the axial button from status "terminal R ON". The LED on the wiper switch indicates that the function is active. A one-off wipe function (acknowledgement wipe) is additionally started. The acknowledgement wipe is also initiated when the wipe interval is increased by means of the wiper-stage switch but not when the wipe interval is decreased.

The rain/lights/solar/condensation sensor initiates wipe requests according to the heaviness of the rain. The junction box electronics analyze the signal from the rain/lights/solar/condensation sensor every 20 ms. For this, the junction box electronics request the relevant signal values and execute the windscreen wipe according to the wipe request.

With the automatic wipe function, the wipe speed depends on the information from the rain/lights/solar/condensation sensor, i.e. continuous wipe stage 1 or stage 2 may be initiated depending on the rain intensity.

Continuous wipe, stage 1

The wiper motor runs at normal speed when stage 1 is switched on with the wiper switch on the steering column stalk. The wiper motor switches from continuous wipe in stage 1 to intermittent wipe if the vehicle speed is reduced down to standstill.

The continuous wipe function in stage 1 resumes as soon as the vehicle speed is higher than 2.5 mph (4 km/h).

The reset (switch-back) of the wiper stage when the vehicle is stationary can be decoded. In this case, the wiper blades operate in continuous wipe stage 1 mode also when the vehicle is stationary.

Fig. 82: Identifying Continuous Wipe, Stage 1

WIPE FUNCTION CHART

1. Intermittent wipe
2. Continuous wipe, stage 1

   v   Vehicle speed in km/h

Continuous wipe, stage 2

The wiper blades are moved at double the speed in continuous wipe stage 2. When the vehicle is stationary, continuous wipe stage 2 automatically switched back to continuous wipe stage 1. The wiper blades then move at normal speed. Stage 2 is resumed again at a speed in excess of 2.5 mph (4 km/h).

The wipe function switches back to stage 1 at a speed in excess of 130 mph (210 km/h). Stage 2 is switched on again at a speed below 127 mph (205 km/h).

Fig. 83: Identifying Decreasing Wiper Stage (Continuous Wipe Stage 2)

WIPE FUNCTION CHART

1. Continuous wipe stage 1
2. Continuous wipe stage 2

   v   Vehicle speed in km/h

The reset of the wiper stages when the vehicle is stationary can be decoded. In this case, continuous wipe stage 2 is retained also when the vehicle is stationary.

Flick wipe

Pressing the wiper switch on the steering column stalk triggers the flick wipe function for as long as the switch is pressed. When the wiper switch on the steering column stalk is released, the wiper movement is completed until the wiper blades reach the rest position.

Windscreen Wiper Anti-blocking Function

The windscreen wiper anti-blocking function is integrated into the electronics of the wiper motor. If the wiper motor is obstructed, the electronics cease the actuation of the motor. The electronics communicate this via the LIN bus the next time the junction box electronics query the status.

A further attempt can be made to switch on the wiper. If the wiper blocks again, it will no longer be operative for approximately 3 minutes.

The wiper interlock is cancelled when the status is switched from "terminal R ON" to "terminal R OFF". The wiper must then be switched on again.

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