Sounds like a dirty switch contact, I had the same problem.

Basically, just pop the door controls out of the drivers door (you have to remove the door panel, or pry up at the base of it, door panel is probably easier/safer, just remove the screw in the little compartment in the door and then the trim around the handle CAREFULLY, and then pry all the clips around the bottom and sides with a screwdriver wrapped in a towel and then pull up on the whole panel. Unplug the window control and just push from the bottom, comes right out.) Once it's out, simply take off the cover, there's a few little clips around it you have to loosen, and once inside use some contact cleaner, and a Qtip and that oughta do it!

Good Luck!

Scott Silverman
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'98 S70 T5-M - Tropic Green w/ tan, Spoiler, Fog Lights, CD-6/CD-3 Changer, External Amp, Cold Weather Pkg, Sunroof