i have no cold air coming out of my left side vents and heat coming out of the right side need help anyone know y. its a 96 a4 12v fwd. heater core and all then been replaced

 

Sounds like a problem with the blend doors inside the dash. Either they're jammed or the HVAC head unit has a problem and isn't telling them to open.

 

I took it all apart and they are opening just no heat. it always worked just fine and all of a sudden no heat. last year i did heater core themostat waterpump and alot of other stuff. is the any way to tell if its the climate control is not working other then using *** obd2 cont

 

I mean vag obd2