WelcomeCustomer The wipers parking in the vertical position is cause by the reversing mechanism on the top of the wiper motor not engaging. What is supposed to happen is the spring loaded lever on the wiper crank arm is supposed to catch on the tab of the motor support. Then the motor turns half a turn backwards to seat the blades. If the lever does not hit the tab, the 1/2 turn backwards means straight up. Often the tam on the bad is the issue. Have a look a the crank arm when you park the blades. Watch to see if the lever catches the tab.