I've had problems with the heat in my truck for two years now, I have tried a few things here and there to no avail. I have back flushed the heater core, and cleaned out the heater box. Cleaning the box helped with pushing more air, but it still isn't very warm. It may blow up to 80 degrees when it's 40 degrees outside. Could I have a vacuum problem? What should the air doors be doing g when I am on "heat" setting? Should it be circulating the inside air,or drawing in fresh outside air??
Not sure if I have this posted in the right place... move it if you need.