First of all, great thread.
I've been having a right old battle with mine today.
Took all the dash out to get to the thermal fuse, went and bought a new one from Maplin.
Got back and soldered it in, fitted back to the car and...... it didnt work
Then i thought of soldering in a single piece of wire to bridge the 2 pins for the thermal fuse.... Still the same
My heater works like this:
Turning to the right, 1,2,3 dont work, 4 does work.
Turning to the left (recirculate) 1,2 dont work, 3,4 works
Could it be a problem with the fan switch?
If anyone could shed some light on this i'd appreciate it.