1995-2002 Range Rover P38A
Without knowledge of the BeCM or door outstaion internal 'electrickery' it is difficult to answer the question. However, I had a similar problem for the last six months or so - front passenger door window failing to operate intermittently. It was all thoroughly checked out with no faults found as it always worked flawlessly when under test! Then it started playing up big time a month ago and finally traced it to a dodgy switch in the centre console switch pack. Disassembled the whole switchpack unit and cleaned out the contacts of the errrant switch and it has worked faultlessly since then. When I split the switch pack I found that a number of the plastic pillars which the locating screws go into were split and the screws were loose and could not be tightened up properly - some super glue and wire wrapping arround the pillars sorted that problem allowing the two halves of the switch pack and circuit board to be located securely. I suspect that the circuit board inside the switch pack was moving when the switch was pressed resulting in intermittent contact. Perhaps you may have a similar problem.