Still blowing air

I agree with 67Dart273. Sounds like you have a blend door that is broken/disconnected or otherwise not working properly. The quickest and easiest repair is to install a manual valve into the heater inlet line and shut off the hot water flow to the heater core. To repair it properly you will need to find the issue with the blend door. I am not sure if it is mechanical (cable) or Vacuum operated.
~Michael