Have a 2003 Ford Focus with rear windscreen wiper washer problems and I am in the process of elimination but need some help. The problems the rear wiper does not work but the washer motor I can hear going ad have that down to a blockage in the tubing or is there a non return valve fitted in the middle of the roof? Also what size is the tubing? I have put th airline on the tubing at the front pillar and can hear the air somewhere in the middle of the roof lining hence I suspect a connector or non return valve. Now the wiper is it stalk or motor problems any tests I can perform other than swopping motors and stalks ? The wipers front work ok with stalk except for the flick which requires constant flicking to return wipers to rest. The back does nothing.