2000 Dodge Caravan does not supply heat to passenger compart

Heater problem
2000 Dodge Caravan V6 Front Wheel Drive Automatic 85000 miles

*replaced thermostat x 2, flushed sytem including heater core x 2.
*raised front of car while idoling to remove any air in system per dealer mechanic
*no coolant smell or visible leaks.
*temp guage reads normal at running temp.
still no heat. Blows tepid air at best

water pump?