Planning the next
AO Silver Member
Join Date: May 2007
Location: United Kingdom
The window stops ( up and down ) by the window controller monitoring the current being used by the motors. When the window reaches the end of travel, the motor stalls, the current demand suddenly changes, the controller detects it and switches the motor off. If the controller doesn't get the correct current limit information, or is itself faulty, it won't stop the window.
The other possibility is mechanical. One thing that comes to mind is the gear quadrant may be damaged right at the end of travel. So, when the window almost gets to the end of its travel, it encounters a missing or damaged tooth and you get the stuttering which also means the controller never gets the current limiting info it needs to switch off the motor. Or, there is some other mechanical fault with the regulator that'll result in a similar situation.
In respect of the first condition, it isn't necessarily the fault of the controller. It could also be that the motor is almost worn out. The fact that it only happens with the window going up, would indicate that the controller is OK.
Does the driver's window appear to move at a different rate to the passenger window?
My inclination is that there is a mechanical fault with the regulator - either the motor itself needs attention or there's a mechanical fault with the regulator.