Quote Originally Posted by silverjoel View Post
Could be as simple as an air bubble trapped in the system or a clogged heater core. I like to use the radiator fill funnels when flushing/changing the chilling system. It's best to squeeze the upper radiator hose to get out all of the air bubbles and do some revving.

You could also flush the heater core by itself as it's pretty accessible.
LATE UPDATE (TUE, DEC 6, 2022 10:38 P.M.) :

It was exactly that, an air bubble! The system had been flushed multiple times with corrosion removing radiator flushing chemicals. So, it couldn't have been a clogged radiator or heater core. I simply didn't know how to purge the coolant system of air, which is why I had no hot air. Now that I know how to purge the coolant system of air, I have a warm heater.

THANK YOU GUYS FOR THE TIPS! BTW, I sit in my truck with the nice warm heater on as I type this. Yup, I'm cozy. 49° Outside