405 electric window, driver's side

[peugeot203]

Hi All, I acquired a quite nice 405 estate (1600 petrol, manual) as a sort of covered trailer that I can use for carrying parts for my restorations and such. Yesterday at a somewhat embarrassing time I discovered the "auto" switch on the driver's side window doesn't shut off, just keeps clicking, until I tapped the up. Then the window doesn't go all the way up. I did get it to go up by holding the glass between both hands and assisting it, but that doesn't really cut it while trying to upt the parking ticket in the machine!
Suggestions for a fix would be much appreciated.