Why don't my heater not blow hot air out

Hello,

There are a few reasons why heater may be not functional.
It could be low on coolant, having a stuck open thermostat, faulty blend door actuator, bad heater control valve.

Here is a helpful guide that goes over the usual issues:

https://www.2carpros.com/articles/car-heater-not-working

One of the common causes of this issue is having a bad blend door actuator. The blend door actuator controls the hot and cold air mix for the blower motor. When the actuator fails it can fail in either hot or cold position.
That actuator is located under the instrument panel on the HVAC box.

https://www.2carpros.com/articles/replace-blend-door-motor

I have attached diagrams for your reference.

Please let me know if you have any questions.
Thank you.