My 126 has center console "double" switches...I assume the 123 is similar. 2 spring clips hold the switch in at the ends. Thin flathead screwdriver will lift switch up slightly and then depress clip...switch should move straight up. Now, the clips may be brittle and break...mine did. Plastic side pins hold the switches together. Open switch over a white towel...there are small "lazy V" plates and tiny metal balls inside. Mine were full of coca cola or something. I used brake parts cleaner and sandpaper to clean contacts.

Probably not your problem, tho....the gearbox atop the lift motor is probably becoming faulty/seizing or may be the motor brushes are worn out/too dirty. I've never seen shops selling just lift motors or just gearboxes....always a combo unit.

For now...try pulling door panel and tapping motor moderately while depressing up switch...you may get window up.

Soon, tho...I suspect you'll need to pull regulator and replace gearbox/lift motor unit. If you do it yourself...CAUTION - spring tension...when the regulator is out on a workbench...removing the 3 gearbox bolts unleashes this tension...the regulator arm and spring plate need a hole drilled thru them and then bolted together or it gets ugly.

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1983 300SD 307k miles
1993 Ford Escort Wagon 215k miles
1995 Isuzu P'up 214k miles