I’m a pretty handy guy and have been working on my own vehicles as well as projects for years but this one has me stumped. My daily driver (2013 f150 limited 3.5 eco boost) just lost heat in the cab. Coolant level is good, coolant system is holding good pressure, and no overheating while driving. Heater is blowing cold outside air but the fan does kick on as it should. Blend motors seem to be working because I am still able to switch which vents run as well as at what speed. Is there some other module or controller that controls when the heater core actually starts heating air? Or what am I missing?

TL/DR: heater no worky, coolant system worky, what wrong