Windows: Description and Operation
Power Windows
Power windows
The front power window drives are activated by the footwell module (FRM), and the rear power window drives are activated by the junction box electronics (JBE). The Car Access System (CAS) performs the central control function.
Brief component description
The following components for power windows are described:
- Power window switch
- Heating/air conditioning control unit
- Power window motor
- Car access system (CAS)
- Footwell module (FRM)
- Junction Box Electronics (JBE)
Power window switch
The switches for the power windows are located in the centre console switch panel. The R60 Countryman also has a safety switch for the rear power window (child safety) in the centre console control panel. Signals from these switches are evaluated by the IHKA control unit.
An additional power window switch in the rear doors of the R60 Countryman are connected directly to the junction box electronics (JBE).
Power window central control (convertible): The power window switch for operating all power windows is pressed and held down. The rear windows are lowered simultaneously. If the power window switch continues to be held down after the rear windows have lowered, the front windows will lower simultaneously.
Heating/air conditioning control unit
The heating/air conditioning control unit evaluates the button signals from the switch panel and centre console control panel (R60). The control unit then sends a message through a body controller area network to the footwell module (FRM) and junction box electronics (JBE). The IHKA control unit is connected across the body controller area network to the footwell module (FRM) and the junction box electronics (JBE).
Power window motor
A direct current motor is used for each power window. Depending on the vehicle model, the drive may also be equipped with a sensor system for the anti-trap mechanism. The window can only be closed automatically (toll function) if the drive has an anti-trap mechanism. The power window drive has to be initialized after repair work on systems equipped with an anti-trap mechanism. Both the closing force and end position of the window mechanism is determined during the initialization.
Car access system (CAS)
The CAS performs the central control function. The CAS is connected across the K-CAN with the footwell module (FRM) and the junction box electronics (JBE). The CAS performs the convenience functions for the power windows. All signals to control the power windows are sent from the CAS on the K-CAN.
Footwell module (FRM)
The FRM processes the requests from the IHKA and CAS. The FRM activates the front power windows electrically. The FRM is connected via the body controller area network to the JBE.
Junction Box Electronics (JBE)
The JBE receives all the signals through the body controller area network. The JBE provides the supply voltage for the power window regulators. The JBE also electrically activates the rear power windows.
System functions
The following functions for power windows are described:
- Opening or Closing
- Convenience opening and/or convenience closing
- One-touch opening
- Repeat interlock
- Anti-trap mechanism
- Energy-saving deactivation of power consumer
- Opening and closing in a convertible
Opening or Closing
The power windows may be operated from terminal R ON. The power window regulators can still be operated for approximately one minute after terminal R OFF. Opening a door immediately stops the operation of the power windows. To ensure that the side windows are securely closed, the power window motors are briefly moved to the locked position (mechanical end stop) end in the top limit position. The side windows can be opened or closed from the following operating points:
- Switch panel in the centre console
- Master key
- Door lock, driver's side
Convenience opening and/or convenience closing
This convenience function is controlled by the Car Access System (CAS). The CAS sends the signal for convenient opening or convenient closing via the body controller area network to the footwell module (FRM). This signal can be triggered using the remote control or the driver's door lock. Convenience closing is activated when:
- the remote control button remains pressed and held after locking/securing
- the mechanical key is kept in the "Lock" door lock position.
Convenience opening is activated analogous with convenience closing using the same operating points. Convenience opening is performed in the following order:
- both front power windows
- sliding/tilting sunroof after a time delay
If the activation is interrupted, the convenience function will stop.
R57: The convenience function is only available for the rear power windows.
Automatic function: opening/closing
Briefly pressing the power window switch will open the window completely. The activation time must be less than 400 ms. Pressing the power window switch again interrupts the power window action.
An automatic window closing function is only possible if the power window drive is equipped with an anti-trap mechanism.
Repeat interlock
A repeat lock is provided for each motor to prevent the power-window motors from overheating. The running time for the power-window motor is limited. The footwell module (FRM) monitors the power window motors. The FRM can switch off each motor individually. The last possible movement is always a closing process.
Anti-trap mechanism
The anti-trap function is active during the entire window movement in the closing direction. The indirect anti-trapping mechanism does not prevent trapping as a general principle, rather it limits the maximum permitted trapping power. When a power window motor is blocked, the current rises above a defined value. Consequently, the footwell module (FRM) ends the activation of the power window regulator. The mechanical forces for the closing procedure vary according to the ambient temperature and ageing. Consequently, the closing force is relearnt each time the sunroof closes, so that the anti-trap function can adjust accordingly.
Load cutoff
To protect the battery, the power windows will not operate while the engine is being started. Every ongoing function of the power windows is halted. If the battery voltage falls below 9 volts, the power-window motors are switched off.
We can assume no liability for printing errors or inaccuracies in this document and reserve the right to introduce technical modifications at any time.
Opening and closing in a convertible
The power window switch in the centre console switch panel for operating all power windows is pressed and held down. The rear windows are lowered simultaneously. If the power window switch continues to be held down after the rear windows have lowered, the front windows will lower simultaneously.
Notes for Service department
Initialize power window regulators
On initialization of the power window regulators, two parameters are learned by the control unit:
- Upper end stop (normalization of the power window regulators).
- Power characteristic curve for opening and closing (learning the characteristic curve).
R57 The rear power windows are not equipped with an anti-trap mechanism and therefore do not have to be initialized.
Preconditions
The following prerequisites must be met to ensure initialization can be carried out correctly:
- Vehicle stationary.
- Adequate battery voltage present, connect charger if necessary.
- Terminal "R" or Terminal 15 switched on
- All doors closed.
The initialization can be carried out using the control switch in each door or the power-window switch block in the driver's door.
Erasure of initialization
Deleting an initialization and subsequent re-initialization can remedy sporadic incorrect shut-downs in the power window automatic mode (toll mode).
Execution
The initialization can be deleted manually by removing the fuse for the relevant power window drive and repeatedly pressing the operating switch.
The deletion of the initialization was successful when the automatic mode (toll function) is no longer possible for the "Close window" function.
Performing the initialization
The re-initialization is carried out as follows:
- Fully open the window by pressing the switch; the window must reach the lower end stop.
- The close the window completely in one action; the top end stop must be reached.
- Hold the operating switch in the "Automatic mode: close" (close toll function) position for a further 2 seconds.
The initialization was successful if the window can be opened and closed without errors in the automatic mode (toll mode).
We can assume no liability for printing errors or inaccuracies in this document and reserve the right to introduce technical modifications at any time.