Not much heat in c15

How come I don’t have much heat on my truck? I have winter front on! And belly tarp when it’s -30 windows go frosty and need to use my Amex card to scrap the window from the inside!! It’s a Westernstar and when I put it in full defrost. There is still decent air flow coming out of the face vents…

 

Difference in temperature is like 8 degrees from in to out of the core! But why can’t I get heat to defrost also? It stays on vent

 

Went up to 185

 

Well I found a space that there’s like 3Ts in the coolant lines. So that could be part of the issue.

 

Yeah when it’s on defrost it’s only coming out of the vents. Don’t get hardly any air out of defrost! I flip it back and fourth to defrost and vent. Airflow doesn’t seem to change. I see the lever switch move in behind that cluster move when I go from defrost to vent then I see a airline but no air leaking