Heater hot intermittently

Hello look forward to your help it has been going on for years. I put a thermostat in your cord it was a Honda part and he did some exactly the same I was mechanic for many years somewhat confused would understand some things or electrically driven. I didn't know if it was a real stat on the heating knob possibly a front door motor I did see some foam come up to the center of dark so I don't know if something's blocking not letting it go to full rotation. Please understand when the heat works it is very hot. I myself would rule out watching the heater core. I am somewhat old school and find I could create more problems than not if it wasn't blowing cold at all I would think that way. Is there a way to test actuator for the hot cold door blend door pull the what you made. If I'm real totally weird let me know. I must note one thing also it does start to get hot as you drive it if you put the defroster on it hinders the operation even more. I found my days working on cars that thermostats on the bottom take a longer time to heat up closest to Foresters on your right there cooling off the thermostat. If I go into the store turn it off start it up the car is hot it would eventually get hot if I drove it just take more time because no wind is blowing on it. I hope this information helps and did not confuse you confusing to say let alone trying to isolate a problem. I'm leaning toward of one door but I just want to go isolated and repair it. My last question is if I scanner on it my friend has a shot will it show what those actuators working? Thank you for all you do enjoy your day happy holidays to you and your family and all that work there helping us get through the day of golden years election nightmares. I will take my little 63 Nova Super Sport all day everyday. Thank you Neil