'2002 - window motor - stuck at fully open

Hi all

After replacing both my front window regulators I thought that would be the end of window issues, how wrong!

Yesterday, driver's window hit the bottom as usual when fully open, however it made a rather nasty clicking sound when it hit.

I returned home and stripped the panel off (can be done in 5 minutes once you've done it a few times ;-) ) I watched the mechanism operate and it would go up fine and stop, but when the window hit the bottom the sensing device doesn't seem to cut the motor power and it rams home hard then click click click - I suspect as the worm gear is very powerful the teeth in the motor assembly are allowed to slip (by their rounded shape) under fault conditions. The window wouldn't then move up at all even with help lifting the glass (I can hear the relay operating), and I had to wait for 5 mins until it cooled.

I stripped the regulator and motor assembly down and reviewed the motor design.

Am I correct in thinking the silver-can in the motor assy is a thermal cut-off? I'm guessing this would operate at window stop based on the huge stall current and disable the motor in the direction of travel - but instantly allow operation in the opposite direction?

Or perhaps I'm totally out here and there's some sort of window position setting sequence I need to go through similar to modern cars?

In my case I reckon the thermal device isn't operating correctly on the down stop, forcing the motor to continue and crunching the gears, it then gets too warm and wont even go up?

Solution - replace whole motor assy?

Island 4x4 - Specialists in Land Rover and Range Rover Parts and accessories for all models. UK and worldwide mail order.

although I'm not sure which unit as I reassembled everything without taking a picture of the motor model number...!

Any thoughts guys?

Cheers
Lea

Replacement motor should arrive today I'll pop it in and inspect the silver can device on the old one and give an update soon.

Lea

Motor arrived, fitting tomorrow

Interesting, it wasn't the motor's sensor at all. The BCU senses motor current and as such detects up and down stalled conditions thus shutting off the current to the motor at maximum exertion. I discovered the issue was caused by poor grade aluminium, see here:

https://www.youtube.com/watch?feature=player_detailpage&v=Fz93vA_0EB4

You can see additional teeth shaped cuts in the aluminium semi-circle - they should not be there. I swapped the LH regulator (it doesn't have these) over to the right and the operation was as expected, when traversing down the toothed cog hits the end of the ali where there are no cut teeth and the BCU correctly detects this stall and interrupts current.

As there are teeth cut into the soft ali of the RH regulator, the motor current doesn't exceed the expected limit set by the BCU and as such the BCU doesn't switch the current off, therefore the action continues past normal stopping position until the glass bottoms out on the emergency right angled stops within the door frame and at that point the motor just comes off the teeth and spins - result nasty clonking sounds and window that wont return up!

Outcome - discuss with supplier and return window regular. Hopefully replacement with a superior ali grade version?!