So I am noticing a slight problem with my HVAC system. I have an '02 disco (with the digital dual climate). When I have the system on auto to a temperature that should be putting out warm air (it is cold here tonight!), the floor puts out the warm air, but the front vents and windscreen put out cold air. This continues all the way up to like 78, at which point I start getting warm air out of the front vents, and really warm air out of the floor. When I put it on defrost I get warm air out of the windscreen, but it doesn't seem as warm as the floor on HI. The same occurs when not on auto

Does anyone know what could be causing this? I looked in RAVE (Mine is for a D2, but they show the manual climate control; am I looking at the wrong manual? I thought all D2s, in USA, had digital) and saw the heating and ventilation schematic, and it looks like it may be a control flap, blend flap, or distribution flap (I can't tell the difference, page 1163 in my version). I thought that it could be a vent distal to the heater matrix, but looking at the diagram, when there is heat coming out anywhere it gets channeled to a common duct (probably where the blend flaps are), and then goes to get distributed up and down and front. Off this picture it looks to me that once the air goes through the heater matrix, all air then simply gets distributed to different vents, but the temps should be the same (since they are coming off a common duct).

Could it be an ambient air sensor problem (is there such a thing)? Does anyone have any insight in this matter (It seems like a PITA to try to correct)?

 

You have a stuck blend door or two.

Example, the door that sends the air to the vents is only open part way and thus not letting all the heat through but the one that sends it to the floor is open all the way.

 

I was hoping it could be something else as that sounds like the whole dash would need to come apart. It isn't terrible, although I do like just putting my cars on auto and not thinking about the temp, if I manually set which vents and the temp I can manage.

 

My wifes car is that way, set the HVAC to auto and 72 both sides and forget about it, its nice.