After 28 years, 88 Supra had this problem, just pulled the drivers and passengers power window switches and cleaned them, used silver contacts, slight amount of oxidation on them. 93 S-10 comes to mind, used copper switches, pulled all four and polished those to a mirror finish. Both shared erratic problems. Other vehicles had cracked wires between the door and the body, these were permanent problems. Drivers switch is the worse, has all those interlocking contacts, clean work bench, and watch out for springs flying out all over the place, all seem to snap together and can be snapped apart.