Pontiac Repair: 96 Grand Prix Heater is not working, vacuum valve, heater core

Question
The heater in my car is not working.  I just replaced the thermostat and it is full on antifreeze.  Any ideas besides replacing the heater core?

Answer
Hi, on the ac and heater control panel. there is a temperature lever it has a cable conected to it. so when you push the lever it will open a door. that is closed over the heater core. to keep the heat out. when the ac is on. the lever may not be opening the door.This may have the vacuum typ where you trun the nob to get the heat on. if it is the vacuum typ then it could be vacuum valve that is not working. And all of this is under the dash.