Wiper and Washer Systems: Description and Operation

Wiper/washers windshield/headlights/rear window

Wiper/washers windshield/headlights/rear window




The right-hand control stalk is moved downward through three positions to operate the windshield wipers. The steering wheel module (SWM) (3/130) informs the central electronic module (CEM) (4/56) of the selected position via LIN communication. The central electronic module (CEM) transmits the information on to the wiper motor module (WMM) (6/1) via serial communication.
To operate the rear window wiper (V70/XC70/XC60), use the buttons on the end of the right stalk.
For intermittent wiping, the process is the same as for low speed, but the time between each stroke is set using the ring on the control stalk to one of eight positions between 1 and 27 seconds. The wiper motor module (WMM) controls this once it has received information about intermittent wiping from the steering wheel module (SWM). The information is transmitted from the steering wheel module (SWM) via the central electronic module (CEM) via LIN communication.
The Wiper motor module (WMM) has an integrated function to protect the wiper motor from overheating and unnecessary wear.
The load on the motor is monitored and in the event of too great a load or high motor temperature, the wiper speed can be reduced gradually or temporarily switched off to protect the motor.
The wiper speed is reset automatically after the load or temperature has reached a safe level.
Washing of the windshield and headlights is activated when the right stalk is moved in the direction towards the steering wheel.
To activate the washer function on the rear window, move the right stalk away from the steering wheel (applies to V70/XC70/XC60).
Then Steering wheel module (SWM) sends information to Central electronic module (CEM) via LIN-communication to activate washing. Central electronic module (CEM) activates the internal relay, which supplies voltage to pump motor (6/104) for the headlights.
When washing the windshield or rear window (V70/XC70/XC60), Central electronic module (CEM) feeds voltage to pump motor (6/127).
The central electronic module (CEM) monitors washer fluid level via a signal from the level sensor in the washer fluid reservoir. The switch in the level sensor closes if the level falls below 1 liter (approx. 1 qt) The central electronic module (CEM) sends the signal to driver information module (DIM) (5/1) via the CAN network. The driver information module (DIM) displays a text message indicating that the windshield washer fluid needs to be filled. The symbol for low washer fluid level lights.
To prevent the washer nozzles freezing and becoming blocked at low outside temperatures, the washer nozzles are heated by means of a PTC element (Positive Temperature Coefficient) in each nozzle. The PTC element controls the heating automatically depending on outside temperature. The lower the temperature, the more heat is generated and vice versa. Heating only occurs when the ignition key is in position II and III. This function is regulated via a relay in the fuse box engine compartment.
The wipers only operate at low speed if there is a fault in the control area network (CAN).