S320 power window auto up/down function

[zibsBenz]

My 1994 s320 power windows are acting strange. The auto up/down function is not always operable. It will work fine for days then unexpectedly stop and then sometimes a few hours or 2days later they are back to functioning normal. At times I've tried successfully resetting them, then at times resetting is futile and low and behold a few hrs/day later they function normally and I haven't done a thing......I never know when they won't function in auto up/down mode. Been this way for a few months.
The steering column settings for up/down works fine but the in/out function is inopperable.
Any ideas ?