Why do I have hot air coming from my vent when thecoolant temperature is be

One or more of the heaters blend doors is either inoperative or broken. Find a good automotive HVAC shop and get it checked. Now that being said, this can get very expensive very quickly so be prepared.

Coolant for the engine has little to nothing to do with refrigerant temperature. If you're getting heated air out the interior vents, as if the heater is on and you can't shift to cool/cold, the problem is likely that the HVAC blend door is stuck on the hot side. One side is for ambient- refrigerated air and the other is for heat. You'll likely have to remove at least part of the dashboard, and it's not a job for a novice.