Heater problem, does anyone have any ideas?

[Rob Graham]

I cant get cold air, the resistor on the controller is working, heater matrix is sound, the door actuator works when i put twelve volts onto the switch wires (opens and closes). Ive stripped out the aircon but i think i should still be able to select cold air straight from outside :S. I can only think it could be electrical. I have read the thermostat controls the water through the heater matrix aswell but ive never come across this before. Any help would be much apreciated

[shavnh]

Did you remove the parts of the aircon behind the dash?

[Rob Graham]

Yeah just the pipe work and little radiator, sorry for the late reply, im on nightshift