Hope this might help you. This was from the Passion4Mopar site, but is now a dead link. I was able to grab this:
How To Test a Mopar 3 Speed Wiper Motor
I get asked this question alot. Seems 99% of the "problems" with
three speed wiper motors is ground related. Gotta have good ground. So, since I get asked the question frequently, I'm going to try to give the answers where you can find them easily...just bookmark em?
If you do not have the proper functions, 99% of the time it is a ground problem. If you experience this, first run a ground wire from the metal housing on switch to the pin switch for dome light in driver’s door jamb. Run switch again. If you still have a problem run a ground wire from the wiper motor ground strap to the negative battery post. Run switch again. If you still experience trouble:
(1) Disconnect motor leads at bulkhead disconnect.
Connect jumper wire from battery positive terminal to brown and red leads in bulkhead disconnect. Connect a second jumper from the green lead to ground. (The ground circuit is completed through the car body). The motor should run continuously. Disconnect leads.
(2) Connect jumper wire from green lead to brown lead. Connect red lead to ground. Connect third jumper wire from battery positive terminal to blue lead. The wiper should run to the park position.
CAUTION: Motor can be damaged if not wired correctly
If you have any questions, please feel free to
contact me.
