One problem related to power window has been reported for the 2002 BMW X5. The most recently reported issues are listed below.
2002 BMW X5 window regulator. Car has 41k miles and already going on 5th window regulator issue. All four window regulators have been replaced and the issue occurred twice on the driver's side window. I have been told multiple explanations from the dealer including lack or use or too much use but this issue occurs on all BMW makes and models. BMW still has no solution that fixes this issue permanently and charges $300 to $600 for each window depending on front or rear. Too much to pay for a bad design.