So, against my better judgement, I bought a pressure switch and as said here, the replacement switch did not fix the issue.
So here is the sequence of events so far:
1. I paid an AC repairman to come out and diagnose the issue.
2. He diagnosed the issue as a 'faulty pressure switch'. (faulty diagnosis)
3. The cost to replace the pressure switch was said to be $550. (I found out through my own research that this part costs 21 dollars)
4. I bought pressure switch and replaced it.
I am going back over to my property tomorrow to do some more evaluation. Since this same AC repairman replaced the control board over the summer, i'm really hoping it's as simple as perhaps he didn't screw in the heat wire into the control board. Or it's loose. Which wire will likely be the heat on the control board and which terminal should this wire be on in the control board?
Does this sound like a good plan?-----
1. Check the control board and make sure all wires are secure and in the right terminals.
2. Check power at the inducer wheel when the Tstat clicks on heat. It should show 120v when it clicks on.
3. Check power at the pressure switch to be 24v.