This is just bringing together info from other postings. I kept needing to find reassurance that I was doing it right and that it would unclip and not break.
The heater on my 2003 old-style Scenic would only run on the fastest speed. To remove the resistor pack I had to:
- Remove speaker covers on fascia to get access to 2 fixing screws
- Lever off the top of the fascia. (It clips into the vertical part of the fascia.)
- Remove the air pipe going to the passenger air vent from the centre of the car. This took lots of brute force to unclip it.
- Unscrew the resistor pack and unclip the 3 wiring connectors. Remove it from the car
Then cut off the thermal fuse and replace it with a new one from Maplins - fasten it on using screw-on connectors (with the plastic removed).
Replacing the air pipe was fiddly and it didn't really click back very well, but it works OK
Total cost - 71 pence for the thermal fuse (I used a 192 degrees one because there wasn't an exact match) plus a few layers of skin from my knuckles. And if there's a next time it will be much quicker.