Climate control did not fix problem. Noticed the problem on defrost today to. Car running about an hour before it happened. I am wondering if the heat is causing the mode door to get stuck in a funky postion. I can hear the fan blowing and you can hear the difference. Its like its blowing into itself. You can change modes, but you just dont get the air volume. After the car sits off for about 15 minutes it fine. I had the car apart and tried to get it do it while I was measuring the voltage at the head, BCM and mode motor, but could not get it to do it for 1.5 hours. Hopefully it will happen on my way to work where I can check it not being in the cold. This is supposed to be the winter car for me. No defrost no can drive.
I've been fighting a similar problem where air blows out of different vents at random, even when hitting a bump in road.
I noticed the lights flickering on the dash climate control unit. The (6) pin white connector on back repeated the problem when I moved it - lights came on/off and air blew out different vents.
The whole dash climate assembly is a Lucas part 58024. I cleaned the connecting pins but also took unit apart (with 3 phillip screws) and found (2) of the (6) pins had cracked solder joint on the printed circuit board. Added a little more solder and the unit works fine.
Thought I'd share in case it might be a problem on other units. About drove me crazy since it was intermittent.
This is just something that worked for may and I wanted to put it out here in case it may help someone else. I have a 04 Stratus and I lost control of hot and cold and it would only blow out the defrost vent. I ended up taking out the control unit in the dash and resoldered the connector to the circuit board. It seems all the joints were bad. After doing this mine has been working correctly for about a month now. So far so good. Hope it may help someone. I guess this has been updated since the last time I looked looks like someone else already posted the same fix but that worked for me too.
I had similar problems with heat not working and cold air blowing out of the defrost instead. It might be unrelated, but this happened shortly after my stereo was stolen out of my car.....forceably. Because of the theft my center console frame was broken in multiple places but would still snap in place. At any rate when I started having the problems I also noticed that all the lights for the center dash stopped working as well(led for heat controls, etc.). That got me to looking at the connections and I focused in on one connection that went into the back of the climate control unit. At fist all I had to do was pull the unit out and put it back in and then the heat would start working. But eventually it seemed that the wire itself was having issues at the connector and I had to literally lift up on the connector and then the heat would consistently work. There is a gap between the connector housing and the climate control unit so I jammed a quarter in that gap and it effectivlely forced the connector up just enough to keep things working permamently :-). I suspect it is bad solder joints as was mentioned above, but me and solder irons are like oil and water so this works for me for now.