I have been off and on issues with my heat, sometimes it works fines sometimes i get no heat. Im thinking its with the blender cause ive flushed my heater core and get good flow thru it. My question is how hard is it to fix/replace and if its electrically or vaccum controlled? and how to do it. I would also like you input on what it could be, since it works fine sometimes other its cold.

Im stuck with its the blend door not letting heat come in and staying on cold or the switch but dont know and dont know how to check. Also when i have it on vent some air comes out of defrost vents is that normal??

Thanks for any help, by the way Jeeps a 99 sport with 4.0 it has the dial controls not slider dont know if that makes a difference??

 

Check for vacuum, if your not getting vacuum under the dash it will move the door and change vents etc.

 

were/what vaccum lines do i check, there's only 1 that i think goes into fire wall and then there is 2 on some sort of ac port??

 

dag. same problem on the heat that I am having. Anyone can answer his question?

 

Disconnect the one that goes through the firewall.
Blow smoke in it toward the cab.
Have someone look under the dash to find the leak - simple!

 

sweet! thanks man.