2001 jeep cherokee lorado heat not getting warm

Hello I am having a problem with my jeeps heat. It is a 2001 jeep grand Cherokee Laredo with the 4.0. The problem is that the heat doesn't work on different settings like floor and defrost. It will work on the setting that I believe recirculates it but when I Chang it to other settings it looses most of its heat. It also seems to loose heat just idling at a red light or when I try to let it warm up. I have looked to see if I have any hose problems and changed the thermostat but everything looks good as far as I can tell. I have checked the lines coming from the firewall going to the heater core and both are hot so I don't think I have a stopped up heater core but I'm not sure about that. I have heard about the doors behind the glove box giving problems but I wanted to get some advice on what the problem may be before I start pulling the dash apart. Any advice would be greatly appreciated.
Thank you

Hello I am having a problem with my jeeps heat. It is a 2001 jeep grand Cherokee Laredo with the 4.0. The problem is that the heat doesn't work on different settings like floor and defrost. It will work on the setting that I believe recirculates it but when I Chang it to other settings it looses most of its heat. It also seems to loose heat just idling at a red light or when I try to let it warm up. I have looked to see if I have any hose problems and changed the thermostat but everything looks good as far as I can tell. I have checked the lines coming from the firewall going to the heater core and both are hot so I don't think I have a stopped up heater core but I'm not sure about that. I have heard about the doors behind the glove box giving problems but I wanted to get some advice on what the problem may be before I start pulling the dash apart. Any advice would be greatly appreciated.
Thank you
http://www.rockauto.com/ Enter you vehicle year and search for heater control
They maybe vacuum or electric I'm not sure which year. If vacuum check for vacuum to the dash control. If electric you will probably have to replace it if doing this get a repair manual at the parts store. They generally have a few pictures.

read up - see if this applies-

www.heatertreater.net

Does the temp gauge on the dash read up around 180 deg. ? I had a problem with the engine temp of my jeep staying too low during the winter. It turned out to be due to a auxiliary fan relay being stuck and causing the electric aux fan on the front of the radiator to run all the time when the engine was running. You can hear it running and probably see it too. It should only run when the engine temp get too high or when you are using the A/C.