This sounds like a blend door problem. A blend door is under the dash it separates hot air from cold air sometimes these doors will stick and only close or open half way usually you can close it manually then the controller will adjust and it will work normal.
There is also a heater control valve under the hood in a heater hose with a vac hose on it if these fail you will have this prob also. Good luck
Saturday, February 5th, 2011 AT 1:18 AM