Hello
I get no hot air coming out of my heating system

This is what I have done over the years to try get it working
Thanks to my student loan i got the radiator, thermostat, all water hoses, water pump and coolant changed
O and i also got the heater matrix replaced - what a pain it was half in the cockpit and half in the enigne bay glad i did it myself saved alot on labour
Anyway I STILL dont get hot air out of my mk2 golf gti (8v)
I heard there may of been a recall on most mk2 golfs many years back and new valve(s) were fitted in the engine bay under the ignition coil. Its connected inbetween the two water hoses and one or two end go into the cockpit
Are these the only two parts i have to change inorder to get hot air into my car.
(P.s - i bought the car 5years ago and its never had hot air coming out of the heating system)
Thanks in advance
ghat