Drivers side power window going down by itself
 

93 Urs4.One day while driving the drivers side window went down by itself.I can put it back up but as soon as I release the switch it goes down again.All other windows work ok.This is intermittent.Sometimes it stays up for awhile then the issue returns.I swapped out the master window switch in the drivers door but the issue remains.I suspect the master window relay but I'm not sure.Anyone know where I can get a used one.Thanks much
Part # 441-959-257-B Siemans 79FA401

Probably the relay, as you suspect. Might be a stuck contact if it has mechanical relay points or broken trace on the printed circuit board if it is all digital. Open yours up and have a look (the cover is held on by 4 little integral pins)

This is the one that you are looking for:

http://12v.org/urs/SunroofAndWindowRelay.jpg

I opened the relay and was unable to find any issues.I can hear the relay clicking when trying to put the window up like the contacts are flipping back and forth on to off.Guess it's time to try to find a good used relay.
Thanks for your input Dave,as always your a great help.

Have you looked at the wire bundle in the rubber boot at the door hinge for frayed/broken wires?

Tom,I haven't looked at that.That's a tight place to look at with that rubber boot in there.Any idea what wire color I would be looking for? Thanks much.

Remove the switch plate (with the 4 switches) by prying out with a wide blade (say 1" or 1.5") putty knife. Examine the colour of the wires coming off the drivers side window switch. (Easier than me searching through the Bentley and you might discover something in doing this).

That was going to be my suggestion also, but I was going to get cute and add look for the copper colored wire (frayed or broken) since there is likely more than one that needs attention.

Removed the rubber boot and what a mess! Wires are in bad shape.The insulation is old and brittle.Some wires broken others frayed.All in need of replacing.This is going to be a big job.On the positive side I was able to splice the correct wires back together and the window now works fine. The passengers side wires are ok.I'm sure it didn't get the use of the drivers side.Is this a common occurrence with these cars? As with most older vehicles you fix one problem and you find several others.Labor of love? Maybe but there's still the word labor in that phrase.Sigh.Thanks for all your help gentleman & Happy Easter to you and yours.

I know there have been issues with the wiring harness going through the trunk on some older Audis (happened on my wife's 95 90 Sport Quattro). I am sure that with age and weather the same could happen to the bundle going through the door.

Ed