Anyone out there ever encountered this particular problem: 2004 Dodge Grand CAravan SXT with 3.8L....defroster works great........will not switch over to heater vents, just produces a hi-pitched whining sound. This particular vehicle is equipped with front and rear heat/ac.

Help!

Thanks!

 

When the body computer detects a problem somewhere in the heating system, it will default to the defrost mode. It's designed to do that because defrost is a safety issue. So there may be many things that could be a possible source of the problem. Browse over to this location and read up on what's reported there.

http://www.lhforums.net/forums/showthread.php?p=267680


I'm not sure about your Caravan but it MAY be applicable to your problem and may assist in troubleshooting.