Hello, my heater is blowing cold. Also when I put the vent on to defrost the windshield, it only works on the passenger side. How do I fix this?

Burp the air from the cooling system.

How do you do that? If you don't mind telling me

Since you are having other damper problems I suspect you have a broken mechanical piece inside your AC box. Look up on how to put your AC controller in diagnostic mode and make sure everything works properly, I have a feeling you'll be taking the dash apart though.