I thought that I can share my observation on rear wiper problem in Megane Sport Tourer 2007. The wiper was stopping in mid position but you could hear the motor is turning. Once helped with the hand the wiper would return to start position. This would happen all the time you tried to use wiper or reversing.
To take out motor you have to remove wiper arm. In my case after removing the screwed nut the aluminium nut sitting on wiper spindle was seized so that even puller could not move it. So wiper arm was cut off (seems to be common solution to this problem on megane, laguna) New arm - £35.
3 bolts undone and then motor can be removed. It transpired that inside motor assembly there is a plastic wheel with side thread that connects with steel screw thread comming from the electric motor. On some distance this plastic thread was gone, thus when the wheel was comming to this point the wiper stopped. I assume this happened because the moving parts seized. The lubricant was quite hard and there were some strange debris inside - like from the wood.
Anyway new motor - was quoted £230 as you can't buy just this plastic wheel. Did not fancy that. So looking on the net could not find motor for megane sport tourer. Then I came across wiper motor from Scenic - megane motor had part code Valeo 8200 153 458-F. Scenic motor was the same part number but -C instead of F. £12 bought on
and it seems its exactly the same shape etc, probably just earlier model. When opened before instalaltion all the mechanism looked like new, lubricant nice and soft, no debris etc. Installed today and works like a treat.
So it looks like scenic second hand wiper motor fits megane, correct code important - not sure if this is the same with other codes . If you have good motor (you can hear it activating) but wiper is stopping mid position than you can have the same problem - damaged plastic wheel inside motor assembly.