Truck heater will not work, change thermostat, blend door is working correctly. After warming up truck intake hose to heater core reads 185 degrees, outtake hose reads 160 degrees , pointed infrared thermometer right at heater core reads 113 degrees.

You got it, I didn't realize there was a second blend door. Thank you very very much. Two quick questions, can I manually close that second blend door through the hole I cut in the back of the glove box to see if the blend door over the heater core was working. Number two, is that the same actuator that opens the other blend door and where is it located.

center of dash at the floor behind that cover on the hump.you will need to remove that bottom cover,then it's right there.

Your talking about the actuator right ,is it the same actuator that opens and closes the blend door over the heater core. I am really appreciative of your help but I'm not following this. I called some part houses and they say there is only one actuator and one blend door , does may be the blend door over the heater core have two purposes and its not opening far enough. Please explain in detail I'm not a mechanic.