Having recently had intermittent problems with the drivers and passengers windows working intermittently then eventually not at all I believe I have tracked down the issue on my particular car and based on what it was I suspect that many others may experience the same thing.

Since the issue was only with the two front windows, and naturally they get the most use, I suspected internal wear in the module. And seeing how a new module at IPD is over $300 plus a trip to the dealer to program the ECM to recognize the new module I was fairly motivated to come up with a solution. Having found a member at Mathews Volvo Forum that successfully cleaned the contacts and got theirs working again, but only for a short period, I took that and went a step further. After a good cleaning with acetone to the rubber pad with the contact points that get pushed against the circuit board to connect the circuit and operate the windows, I applied a dot of silver conductive wire glue to each point, let dry, gently sanded with 1500 grit sand paper, reassembled, and Wala, fully functional switch for a grand total of less than $10 and about an hour of my time not including the dry time. Hope this helps someone.