Audi Repair: Heating problem, vacuum leak, blower works

Question
My question is my heating don't work but the blower works and the AC works. And it only blows out cold air. Within a touch of the button it just quit. What is it that needs to be fixed in order for my heat to start working?

Answer
Chek if the heater is getting hot, i.e. if the heater valve still works.  Both hoses going into the passenger compartment behind the engine should be very hot when the engine is hot.  Could be the controller, or a vacuum leak, or a stuck valve, or a stuck deflector flap.  Check the hoses first.
Let me know,  Jan