From Newsgroup: uk.rec.cars.maintenance
The window control box is on the door panel on the UK R20. There have been some on ebay secondhand for about -u50. I have exactly the same problem. This box is the likely problem. Swap one from another door and see if it changes the behaviour.
Nuisance that it only goes fully up or fully down. Passenger door does NOT do this. That issue of intermittency may be a poor supply out of this control box! Could be a simply naff relay in that box increasing the circuit resistance.
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