According to my information, you do not have a separate module, the rear wiper motor has logic in the motor assembly. At the moment, I would pull the rear wiper fuse, ip fuse block, that should kill it, until you find the problem. That rear wiper fuse is hot all the time. The rear wiper switch is part of ground circuit. The BCM can also supply voltage. Note the diagrams, I can only help with testing.
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Saturday, September 2nd, 2017 AT 11:30 AM