1996 EVO M3 UK 118,000 miles.

Normally, when the door is shut, the glass window raises a little to
effect the airlcok and when the door opens, it lowers itself an inch or
so. This is for airtight locking of doors, I presume.

My passenger side window stopped doing this suddenly. The electric
controls work normally and I can raise or lower thw windows with the
press of a button but the window doesn't raise itsefl that last inch to
effect the airlock. At motorway speed, there is the whining air noise.
The driver side window works fine.

Anythoughts as to what can be wrong and if it will be expensive to fix?

TIA

Vijay.