Front Door Window Regulator: Description and Operation
Window Regulator
Cable operated window regulators powered by an electric motor are installed in each of the doors.
Front Door Window Regulator
Rear Door Window Regulator
OPERATION
Electric window operation using the window switches is enabled while the ignition switch is in positions I and II, and for 16 minutes after switching from position I to position 0. Window operation is immediately disabled when a front door is opened
When the switches in the driver's door are used to operate the passenger windows or the child lock, the driver door module outputs a related message on the P bus. The passenger door module or the GEM respond to the message by operating the appropriate window or the child lock function. While the child lock is engaged, the GEM ignores inputs from the rear window switches, and the driver door module illuminates a LED in the child lock switch.
End of Travel Shut off
End of travel shut off for the window motors is determined by monitoring the current draw of the motors. Each time it switches on a window motor, the door or GEM measures the window motor current for 22 milliseconds, in 2 milliseconds intervals. The maximum value measured within that time is stored as the switch-on current, which must be 5 A minimum. When the window motor current next exceeds the switch-on current minus 2 A, the door/GEM assumes the window has reached the end of its travel and, after 0.5 second, switches off the power supply to the window motor, even if a window switch is still being activated.
Measuring the switch-on current for each switching operation automatically compensates for changes of load with varying ambient conditions etc.
To protect the window motors from overheating if the end of travel shut off function fails, window motor activation in both directions is limited to 8 seconds.
One-shot Opening and Closing
One shot opening and closing is activated by selecting the second switching positions on the window switch. One-shot opening and closing is enabled on all windows except on Australia models. On Australia models, all one-shot operation is disabled except for driver's window closing.
Anti-trap
The anti-trap function is enabled for window closing in both the inching and one-shot modes. If an anti-trap sensor is activated while a window is closing, the window motor is reversed for 0.5 second.
UK models feature a longer reversing time after a trap detection. The reversing time is proportionate to the preceding closing time and varies between 0.5 and 2.0 seconds.
In an emergency, e.g. if the anti-trap sensor is faulty, the anti-trap function can be overridden by holding the window switch in the one-shot closed position.
Convenience Opening and Closing
Convenience opening and closing is enabled provided the ignition switch is not in position I or above. The windows and roof opening panel (where fitted) can be opened and closed in sequence, while unlocking and locking the vehicle, using the driver's door lock or the remote handset.
Convenience closing begins after a time delay of 1.5 seconds when the door lock is held in the lock position or the remote handset lock button is pressed and held. The anti-trap function is enabled during convenience closing. The closing operation also stops immediately the door lock is released from the lock position or the remote handset lock button is released. The window motors are switched in pairs, with the rear ones switched first followed 1 second later by the front ones. The roof opening panel begins closing when all of the windows are closed or 3.5 seconds after convenience closing started, whichever occurs first.
There is no convenience closing on NAS vehicles.
Convenience opening begins after a time delay of 2.5 seconds when the door lock is held in the unlock position or the remote handset unlock button is pressed and held. The opening operation stops immediately the door lock is released from the unlock position or the remote handset unlock button is released. The window motors are switched in pairs, with the front ones switched first followed 1 second later by the rear ones. The roof opening panel begins opening 3.5 seconds after convenience opening started.
Operating the windows and roof opening panel in sequence allows a degree of selective operation, e.g. the windows can be closed and the roof opening panel left open when locking the vehicle and using convenience closing.
Repetition Blocking
To prevent the window motors from overheating, the door modules and the GEM record the run time for each motor they control. The run time, in seconds, is added to a counter on completion of each activation, and one second is deducted from the counter for every three seconds the window motor is inactive. If the counter exceeds 60 seconds, no new activation for the window motor is accepted until the counter is below 60 seconds again. The only exception is a reversing operation triggered by the anti-trap function, which is always accepted regardless of the counter value.