Heater control issues 2003 Dodge Ram 1500
I know that these trucks have bad heater doors but my truck may have been worked on previously because the heater core has aftermarket hose clamps on it. The trouble I am having is I have good air flow to the defrost and vents and floor I can hear the recirc door opening normal and I did check the doors and they all appear to be working normal but when I want to increase the heat by turning the temp to the red zone the air gets cooler if I put the knob in between the red and blue on the temp zone that is were it seems the warmest I have read that this may need to be recalibrated? I am stumped. Any help would be appreciated!!