No Heat, only Cold Air

Over at the Dodge forum everyone's asleep. I know you guys here will know the answer to this, you have helped me many times with my Pontiac! Our son's 2001 Dodge Stratus RT only blows cold air when the heater is on. It worked fine last winter. The heater hoses are warm. What could be the problem? All advice will be appreciated. Thanks much.

If both heater hoses are warm, it's most likely the temp mode actuator isn't pulling the door to force air through the heater core. I'm not sure if the actuator is vaccuum or electrically operated, but that's where I'd start looking.