As for the fan I just did this myself. It's the resistor pack on top of the box. I cut out the thermal limiting fuse and soldered one in. Cost me a couple pennies. My fan motor was on the way out though. Fixed that too. You can get perfectly fine resistor packs at the breakers for cheap. However, understand WHY the fuse went. Your heater motor may need some lovin'.

Part? 128°C (262.4°F) Thermal Protector Fuses
Where? http://www.torreelectrics.co.uk/acat...use_links.html

Rev counter could be a cold solder joint. My car was off the road for some time and it was lazy. I (just today) resoldered the entire circuit and it works fine.

Not bad at electrics for a colour blind guy eh?