Just thought I'd post my experience on my 2002 Scenic with air con & electronic environmental control.
Last week the blower fan just stopped working when I started the car one morning. I checked the fuse, but it was ok. I checked on this forum and from the information gathered I deduced it must have been the resistor that was at fault. The second-hand & refurbished ones on
were about £30 (inc p&p) My local GSF Car Parts had a new one in stock for £46 so I opted for that instead rather than wait a few days and take a chance on second-hand parts.
I removed the top section of the dash as per the instructions from earlier in this thread.
The pipe that needed to be removed runs across from the back of the passenger air vent to behind the clock unit - it's covered in a thin foam, but it's just a shiny black hollow plastic pipe. It took a bit of effort to wrench it out of place, but one or two good hard pulls and it will come out (putting it back turned out to be the hardest part of this job!).
With the pipe out of the way you can see the top of the resistor with its distinct green connectors. To get to it you need to remove the electrical connection block sitting above it - it's just secured with a single 6mm bolt so loosen, lift up and push to one side. Disconnect the green connectors from the top of the resistor, loosen/remove the two 6mm bolts and lift the resistor up & out. A magnetic pickup tool would be handy as the bolts are fiddly and difficult to keep hold of once loosened.
Before I went to collect my new resistor I took the covers off the broken one to see if I could fix it, but there was nothing I could do - no obvious thermal link etc!
I popped the new one back in, replaced the connector block and then struggled for 5 minutes to get the hollow pipe back into place - I found it helped to pop out the passenger side vent so I could see the alignment of the pipe. Once that side was in it was just a case of pushing, shoving & wriggling to get the other end back in.
After that I replaced the dash and the blower fan now works a treat! Total time 30 minutes.