Heater control panel
 

I took the heater control panel from my 90turbo and put it my wifes 87NA and the everything works OK. I don't think the panel changed during the Mk3 production. I've bought a panel for ?25 from a scrapyard but haven't fitted it into mine yet. I took the broken control panel apart all looked OK the slide contol seemed to be a sealed unit but I'll try taking it apart for cleaning.
The resistor for the heater lies in the air duct on the bulkhead at high level in the passenger foot well. The smallest coil that contols the first setting of the fan breaks or falls apart. It can be repaired as described in the other replies - life is too short - I bought a new one!
Another problem I had before was the fan not working at all. I took it out and found the motor full off dust and dirt it seems to find its way in through a black tube which I think is for cooling. I cleaned the motor up and put a piece of linen over the end of the black tube to act as a filter - its been OK since.

Done. I replaced the broken coil with some fuse wire of about the same gauge, wrapped it around a pen, 10 coils like the original. Works like a charm. Allthough the surfaces were really filthy and took a bit of rubbing with emery paper to get the solder to take to it. Thanks again for the help.

hi, just got a '90 7mgte manual in black/pearl mica, i think i got a BHG (gives a little puff of smoke sometimes on down change) freind thinks it could be the valve stem oil seals? either way i'm gonna have the head off. get it skimmed and new gaskets sets in. got the same heater problem (fan blows but only cold air), i'm a bit of an novice when it comes to getting my hands dirty and all the technical stuff. as i'm in the uk, i'm guessing that the vsv is going to be swapped over on the opposite side as we have our sterring wheel on the right here. thats right yeah? and where exaclty is it, can i access it from the footwell inside or in the engine bay? any help/pics would be great.

It is located next to the heater water valve, and always feeds vacuum to the water valve...except when the controls are set to 65*, for max a/c cooling. That's why you don't really need the vsv. Just bypass it and hook vacuum directly to the water valve. Out in engine bay on firewall.

my air blows fine, but it doesn't blow hot or cold.

It doesn't matter what the temp is turned to, it just blow outside air (or recirculated, if that button is on). If i turn the AC on, the fan clutch kicks in and the air speeds up, but it does't change temp at all, so in the summer, i roast without putting down the windows, and in the winter, i freeze......HELP!