I checked the usual stuff and changed the heater door actulator because it was faulty. Air when heat is on is room temp its not hot or cold. top Hose going into heater core was cold but the bottom one was hot. Also the hose assembly was hot. Do you think the hose leading to heater core is clogged or the heater core itself. Mechanic wants to charge me 800 to do the work. I plan on doing the job myself in the spring. Any advice I would be grateful

 

that is a reasonable price.
if the temp blend door is moving then it probably needs a heater core.
not sure your model year...most are a 9 hour job as the dash will have to be pulled back far enough to remove the hvac box, the box split open the heater core removed.
find a video on you tube.