2003 Chevy Impala 2003 Impala. Drivers side wiper off the w

2003 Chevy Impala 70000 miles

2003 impala. Drivers side wiper will move off the edge of the winshield. This wiper arm can be moved by hand back into the lowered position and is moveable with the wipers off where the passenger side will only move slightly. Just by removing the cap and the bolt I can see that the arm with the bushing will rotate around bolt. Retightening this nut with the drivers side arm down in the parked position will allow the motor to pull the wiper back but the top 3 inches or so of the blade will still cross over the edge of the winshield. Any ideas?