Welcome to C3VR!
First, check to make sure the wiper switch itself is grounded properly. The wiper motor always has voltage(with the key on). The wiper switch provides the ground for the wiper motor. If the switch in the dash is not grounded, the wipers will not work properly. Most people run a separate ground wire from the metal bracing behind the dash to one of the screws that hold the wiper switch on the cluster panel, just to make sure the switch has a good ground at all times. The switch grounds thru the panel, to the metal dash...if the screws are loose, or missing, the switch may not ground right, so it's easier to just run a ground wire to the switch screws.
This is why a lot of folks can't figure out why their wipers don't work when they have the cluster panel loose working on it...the switch is no longer grounded at that point.
hth

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Joel Adams
C3VR Lifetime Member #56    
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