Iíve got just about the same problem, Laguna II 2001. The fan is not working at all. I found the the water-outlet from under the windscreen was blocked and has passed water through to the blower and motor.
Iíve cleared the blockage and have checked the fuses behind the glovebox which are all fine. When removing the pollen filter I found a large amount of rubbish (itís not been changed for a lot of years) which some of it has now dropped into the blower. So now Iím wanting to remove the blower (to remove all the rubbish and clean it out) and the motor (to check it electically and DRY IT OUT!)
That being said, Iím less than a novice at this and as such Iím struggling to actually get the blower unit un-mounted. I found a couple of images from a haynes manual talking about retaining bolt(s) but the image is a mess so I cannot see where these are! Looking up at the motor/blower Iíve managed to un-screw around 7 bolts from the top of the blower but there is one bolt at the back that I cannot reach!
Please could someone help me to remove this unit?