thanks for your help
The year of the car is 1982.
Yes, I can see the wiring colours. They are brown with a white strip and black with a red strip. I have looked often for them on the wiring diagram in the Haynes manual. There seems to be a mistake with the wiring in that they have swapped the captions for the UK and US models. i was hoping someone would have amore detailed wiring diagram or could help me with terminaolgy with the temperature control circuits so i could zero in on what element is fused. The temperature controller still works to som edegree as the fan speed is controlled correctly, ie it comes on fast when it needs to cool/heat a lot and goes to idle when the temepratures are equal.
With information gained from previous posting I removed the heater control valve. The daiphram is total gone. Until I get the heater control electrics back to working order, using a cable tie I have permanantly forced the heater valve closed. Much more comfortable using the car, and I notice when the AC is working. I will need to order the Heater control valve repair kit.