Why is the Defroster/Vent blowing cool air with heat control full on? on 1997 Ford Aerostar

Even after driving 5 miles the front air system only managed to blow lukewarm air. The engine was at normal operating temperature after a couple miles. What do I need to do to resolve this issue?

Asked by for the 1997 Ford Aerostar
Confirm that both heater hoses are hot to the touch, that ensures good coolant flow through the heater core, and if that is OK, then you may need to repair the temperature blend door and/or its actuator. The blend doors are known for breaking where the actuator connects to it.