93 Caravan Rear Wiper Motor

Here is a good one.

I picked up a new rear wiper motor from Chrysler (under the Recall for
blowing fuse). Intermittently (more often than not) the new motor runs all
the time ignition is on, regardless of switch position. I have checked to
pod switch is correctly and consistently applying the 'on'
ground to the rear wiper module. I have tried exchanging the rear wiper
module for another in service module - same thing. I have checked all the
wiring for continuity and shorts and found nothing wrong.

I'm not convinced the modules are working correctly, as the one test that
checks for module operation does not test correctly, but also I'm not sure
the test makes sense. On the two wires to the motor, one has ignition
voltage any time the ignition is on (this one is correct). The other wire
should have voltage when the ignition and wiper switch are both on, voltage
coming through control module, after the switch ground is applied to the
module. This appears to be where my problem is, but both modules are doing
the same thing, and both intermittently. I also don't think the module (just
a circuit board) should operate so intermittently. I spoke to a DC
electrical mechanic and he indicated the new motor should be a straight
swap, no other mods required.

Has anyone had a similar experience, and recalls what the fix was?

 

Have you actually checke dhte wiper switch itself?

 

Yes, the instrument panel pod switch is correctly applying the ground signal
to the control module. And that is a solid firm connection.

I think I'm trying to confirm if I got a bad motor from Chrysler, or if I
have 2 bad control modules, or if there is actually a bad wire somewhere in
the tailgate harness that I have not found yet. The motor itself seems to
check out fine, including the Diode and the wipe contact connections. the
modules - who knows, its full of electronics.

Thanks for input.