Changed thermostat thinking that was the problem. Heater hoses to heater core(s) are hot. I can see the blend door actuator rotate about 90 degrees behind the radio.

It will puff a bit of warm air when RPM's are a bit higher.

Again, the heat is cold front and rear.

Can the cores be plugged? But then both hoses would not be hot? I would imagine 1 to be cold if it were not circulating.

Thanks, Matt