The passenger side mirror on my V70 has never worked. Got another one at salvage yard, still not responding. I took the salvage yard mirror and connected it to the driver's side socket and it works fine. So it appears the problem is not the mirror. The little red light comes on when i push the R button, but nothing moves. This is a minor problem, but still annoying.
The more serious issue, the driver's window is now acting erratic, sometimes does not want to go up, other times does not want to go down.
All of the other windows operate properly.
Can the whole switch module be disassembled and cleaned?
i thank you in advance for your comments.

The driver’s window issue sounds like an electrical contact problem. Yes, you can carefully take out the switch and clean it and its wiring using electrical spray cleaner. While there check the condition of wires. Those switches can be delicate. Be careful!

The passenger mirror sounds like a wiring issue. Maybe there is a break? Did you examine the wiring’s condition when you installed the junkyard mirror? I’m no electronics expert but you can do an electrical test to see if electricity is reaching the mirror.
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Will I buy another Volvo??? We'll see....

Yes, the switch module can be opened up and the internal contacts cleaned. It may take multiple tiny screwdrivers to release all of the little barbs simultaneously. You’ll see what I mean once you get the module out of door panel. You can almost pop the module right out of the door panel except for a screw that holds the bottom of the module to the panel. That screw is likely tight enough that you’ll have to remove the door panel to loosen it. (The screw hole in module is an open slot.)