Has anyone else experienced this or can tell me what to do? I have an 01 Navigator that produces heat and A/C, but it will not move out of “Defrost” mode. Ever. The display tells me that it is different, but it continues to blow the air only on the dash. The high/low function works fine as well as the temperature. The rear heat and A/C works just fine, too. Is this a fuse issue or something worse?
You have a bad vacuum connection from the engine to the climate control module. The module switches vacuum around to open and close the various air doors. When there is no vacuum, the defrost outlet is where all the air will go. It should be easy to find and fix, and cheap.