Start with checking the fuse
Move on to checking the wiring going into the motor.
And finally, you may end up with a new wiper motor.
See "Related Questions" below for more
most likely the switch is bad, or the wire plug has a bad connection
Strange as it sounds, check the transmission range sensor / neutral safety switch.See "Related Questions" below for more
Diod you check front brake pads
in this case, the positioning switch in the wiper motor is out of order.
Use the same switch for the front wipers. Once the front wipers are switched on, the rear wiper will come on as well. However, a reverse twist of the switch would turn on just the rear wiper.
Having it on "PARKING"
It could only be either a fuse, the switch/or wiring, or the motor burned up. I would check the fuse 1st.
vacuum leak
bad switch off the steering column.
Fuse or windshield wiper motor.
your car stalled?
a dead battery