Hi, The control unit for the sensors is under the passenger seat. The problem seems to be the plastic hose that serves the rear window wash separates during the cold weather and water leaks/pumps into the passenger footwell.The hose im refering to runs under the kick plate where the carpet joins the side of the car (passenger side).Remove this plate and rejoin the hose with duct tape or something to stop this happening again. If you dry the unit out under the seat there will be a chance it will work ok. Best of Luck Scott B)