96 cutlass supreme heat problem

Alright, i have a slight predicament. the heat in my 96 is not working. Also you can't adjust the temperature on the A/C either. Does this sound like my controls are going bad, the mixer is not hooked up completely or could my heater core be clogged? the head gaskets blew some time ago but were repaired but the core was not replaced as far as I know. any help would be greatly appreciated.

Look for both heater hoses to the heater core getting hot for starters.