had the same problem with my 03 Jeep Overland --- the problem is the ' heat vent solinoids 'and when one goes the other is not far behind,, this is a big problem with Jeeps new heating system and to make matters worse - to replace them is a big pain and the dealer wants BIG money to do the replacement. My Jeep is down in Washington state and I am up in Alaska and my friend had to get this fixed without me being there and she found a Jeep mechanic that knew a few tricks to make this job easier and the whole thing cost only 150 dollars instead of the 1,200 that the dealer wanted ---- if you have a mechanic in your area that you know and trust and would like to have do the work -- I can get you the phone number of the mechanic in Washington and they can talk and share this ' trick of the trade ' ( or if you are mechanically inclined and want to take this fix on yourself - I am sure he can walk you thru the steps ) + give the info to where he bought the parts at such a reasonable price.
just let me know -- you can e-mail me directly at ' firstname.lastname@example.org
',, the earliest time that I can get that number is around 6pm PST 1/21/11.
again -- the part that is broken is called the ' heat vent solinoid ' - so if you want to call around to some local Jeep mechanics to see what they charge for their replacement AND just for fun,, call the dealer and ask them - ( they are crazy !!! ).
have a great night,