wipers

[B@fink]

My wipers seem to have taken a turn for the crazy. Last time i used them they worked just like they should, but then after i washed the car (possibly a red herring) they have gone slightly loopy. The first time i used them i was just "flick" wiping the condensation in the morning and they wipe and then jump up an inch! So i tried them at slow speed and then turned to off and the same and then full speed, the same and then intermittant.......you guessed it.....They still wipe and then do a little more just for no reason! Is this a typical sign of wipers on the way out or are they just getting giddy after having a bath?!? I would think they have a stop switch in them but i'm not pulling it to bits if i don't have to.....anyone seen this before?!