2006 Porsche Cayenne S front and rear wiper failure
 

Hi:
I recently purchased a 2006 Porsche Cayenne S with the front wipers not working and the rear wiper arm missing. I removed the front wiper motor and mechanism and found that there is 12v power at the plug. The rear wiper I assume was stuck on and the arm was removed by previous owner for quick fix. Stuck on rear wiper seams to be a common issue.

Currently both wipers front and rear do not function but the control on the steering column activates the washer pump, nothing else.

What to do next, I am stuck, any ideas on a course of action to determine what is wrong here? Or what to replace? Rather than replace everything.

Any thoughts?