69 B Body 3-speed wiper motor. Darn thing runs great going forward in all three speeds, but doesn't park. Tested switch and was OK. Removed motor and bench tested according to service manual. Jumped brown and green wires, grounded red and put 12V to blue wire so motor should run backwards, but won't?? How can it run forwards OK, then when I switch polarity, it's dead. I'm not a wiring rocket scientist but what's up? Jules...HELP!

Whenever I've benched tested one, I ran four jumper wires from the bulkhead to the harness plug on the wiper motor of interest. Also ran a separate ground wire from a good ground location on the car to the case on the wiper motor. Five wires altogether and each of some length, but never had a problem testing one. Requires good wiring (and switch) in the car, but if the switch and wiring are known good, you might try it.

Could be several reasons but the main one is mostly likely that the switch plate contact point is either open or has some corrosion
preventing the switch from closing properly. Did you remove the switch plate at the front and check the contact?
You can call me if you wish 450-656-5438
Jules

Other possibilities:
Blue wire is not soldered properly to the switch plate terminal any longer.
Blue wire may be cut inside.

Jules...Yes, I removed the cover and cleaned the contact points before testing. Is it possible I installed the cover with the cam in the wrong position? Are the points open or closed when the motor runs in reverse before parking? Is there a trick to installing the cover plate?
Thanks

I think you do have position the cam and switch cap correctly. See this post for details:

https://board.moparts.org/ubbthreads/show...rue#Post4884645

Frank the points should be closed with a slight pressure on the contact point.
The positioning of the switch is important but you stated above that your motor does not run in reverse
so that would not be the issue here.Check continuity between the plug terminal and the switch plate
terminal of the blue wire.Check also continuity between the 2 terminals of the switch plate. Sometimes the
points look clean but there maybe be a burn spot. While you are at it, check continuity between the red and green
and then between the brown and the large green wire soldered to the switch plate.
Jules
450-656-5438

Thanks for the posts. Pretty sure I didn't install the switch cover correctly now. Will work on cover and continuity tests tonight.

HAAAA! Jules was right again. Even though the points were clearly closed, the curcuit was open between the gear cover tabs. I cleaned and rebent the contact arm slightly to ensure full bearing on the point surfaces. Now it works like a charm.
Thanks all for input.

Success!!!
Good news indeed.
Jules