I to have a Renault Laguna Dynamique 02. Tnhe rear wiper sytem became faulty. Eg, lose and not sitting correct on the window. On my car the mechanism is not part of the screen. It can be found under the tailgate trim which easily clips of from the top. On doing this I discovered the mechanism bolts had all worked loose. It took 15 mins to complete the job.
Hope this is of some help.
I am also having problems with a faulty passanger side electic windon!!
Rob B
April 2007