There are two different types of window control unit and switch pack, and the changeover was sometime in 2008. If your replacement switch pack is of the wrong type then it won't function, so make sure the old and new ones match exactly. It doesn't help that the connectors are the same type, but the later version has some of the connector pins missing.
It's also worth checking the door wiring harness to the A-pillar. From your symptoms it's not the most likely cause, but it's relatively simple and might make a difference. Disconnect the connector on the door and check pins for corrosion, or powdery deposits and clean them if necessary. Make sure you disconnect the battery before doing this or you will get an airbag warning light.
If that's not the issue, then it is most likely to be the electronics module on the window winder motor. You can replace this with a unit from a breakers yard if the part number labels match. If you buy a new one from Volvo, then it will need to have the correct software uploaded to it after it has been fitted, as they only supply new ones with basic software and this needs to be updated to match the options fitted to your car.
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