My wipers won't park when I turn off the switch, they just stop in what ever position they happen to be in. Could this be a problem with the switch or wiper motor? How do I find out?

The motor ground not connected will cause the problem you describe. The motor has a park switch, when the wipers are not in park the switch is closed completing the motor low speed circuit. When the dash switch is turned off the motor runs until the wipers reach the park position, the park switch opens and motor stops. The motor has three mounting screws, one screw should have a ground strap attached.