I have a 1993 190e saloon and all windows roll up great but my driver side window stopped rolling down. I know it has to do with the switch because before it stopped entirely I could move the switch towards the left and it would roll down like it should with ease. How can it be fixed and what do I need? Thanks.

Need to get a wiring diagram. Buy a book and follow the wiring schematic. It should help you out majorly. Can't really work on electrical issues without one.

change the wire leeds around

Drivers front or rear?

If its the drivers front window the master window switch is the problem. If its one of the other three windows its going to be a little trickier to figure out if you need to replace the individual switch at the door or the master switch.

If its the drivers side rear you can hit the window lockout button on the master switch. If the window stops rolling than its pretty safe to assume the switch on the drivers rear door is bad. If it still rolls down with the lockout on than its a pretty safe bet the master switch is the likely problem.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

replace the switch. They have parts made of plastic pressing on the contacts softing these babies up making them useless in a few years

This problem is very likely caused by the drivers side power window switch being defective, I have seen this very same problem in the shop more than once and the new master switch fixed it. here is the part number and price from www.Rockauto.com
AIRTEX Part # 1S3874-Left front Power Window Switch. Price $105.79

try to replace switch or check your wiring might be broke

REPLACE THE POWER WINDOW SWITCH

most of the time it is wires in the drivers door that break in the loom

well check window switch on driver side first does it roll down from that side / does it roll down from passenger side/ next if not do you hear the motor if yes its the switch in driver door that is bad / if you don here the motor then its the regulator/motor that needs replacing/ Please rate my response thank you very much

I think that the switch itself is losing contact. By switch I mean the button you are depressing to roll up the window.