It is getting colder out there so I turned on my heater and it worked fine for about 20 minutes and then slowly the amount of air coming out decreased until no air was coming out of any vent. Below is what I have been able to find out...

1. No air will come out of any vent setting even when I change vents
2. Airflow starts out fine but decreases slowly until no air is coming from vents
3. Only occurs when heat is used. AC is unaffected
4. If I pull out the glove box and knock on the floor vent it will slowly start to work again but will eventually stop
5. Parking and letting it sit for a while, like going to work, and it will work when the car is turned back on
6. Turning off the jeep does nothing unless it is for an extended period of time
7. The heat setting it is on makes no difference it will still occur even if it on the lowest setting or super volcano
8. Fan setting has nothing to do with it
9. I can hear the fan blowing just fine just no air coming from vents

Is there a blend door or anything like that that has the ability to shut off all airflow at the same time?

 

It would help to know the year of your JK, and what the HVAC has for automatic controls.

 

Sorry about that I have a 2008 JK Sahara, I dont know about they type of heater controls as i thought they were all the same in this year range.

 

I finally found a diagram of the Jeep heating system and it looks like if the blend-air door is closed it is the only one that will stop all heated air from coming out of any vent. So I am assuming that it is a problem with the blend door actuator, as I have read there are issues with them going out, however I cant seem to find any information on how to replace them.