I am having issues with my defrosters, when i turn them on they blow freezing cold but when i take off the defrosters and have on the floor or vents its hot air. I have done a flush and a new thermo. Any other ideas?

There's a problem with a "blend" door,or whatever controls it,could be switch malfunctioning.Most all that is up under the dash.Look under the hood for vacuum lines under the hood and firewall area being broken or disconnected.