I believe that it is the motor, on the drivers side window.
drivers window on 1999 Plymouth Prowler
If the window has failed, the motor and/or regulator will need to be replaced. This is not a "do it yourself" job, as the access is poor, the sheet metal is sharp, and you need a large rivet gun to fasten the components. I would recommend seeing a qualified technician. Here is a link to some shops near you.