I just purchased my first Mini and love it. When I use my rear wipers the one on the drivers side will work once and stop. The other one will continue working and stop and go back down below the glass in the horizontal position. The other one will stop where ever it wants after a few swipes. The only way I can get it back down below the glass is keep turning it off and on. And this usually takes awhile. Is this normal? Any help would be greatly appreciated.