I have a 96 Dakota that I bought used with 51000 miles a couple months ago. There is evidence that the previous owner had replaced the heater core. My problem is when the truck is hot and you put the temp selector over to hot it feelf like very little air comes from the vents. Its the same whether its on defroster,dash or floor. BUT, when you slide the temperature selector over to cold there is an immediate increase in the force of air coming through the vents. I assume there is a problem with the blend doors but I have never got involved with any hvac issues before. Any help with diagrams or info would be great.

PS: There is a new 180 degree stat in the truck. Both lines to the heater core get hot. Thats why I assume it might be a blend door problem.
Thanks Again

 

does it do it when the fan is on high? if so your blower fan could need replacing[/align]

 

The blower fan is fine. If it is moved over to cold the bower works from low to high just fine. Its when its moved over to hot that the air coming out of the vents feel constricted. (Very little air)

 

it probly has something to do with your blend doors.

when mine sat for a while in the summer out side I got alot of leaves that clogged my vents, so I had to rip it apart to get all of them out.

but when I put mine on heat and defrost. theres more that goes on the floor then defrost.

 

How did you get at it? From the top by the wipers or through the inside under the dash.

 

I had to get at it through both ways. it was clogged to hell. I keep it stored inside now when I'm not driving it.

I can still hear leaves that get caught in it once in a while and they hit the fan and stay there for a while. its that stupid sound when you stick a card in the spokes of your bicycle. [:@] it drives me nuts. I just have to play with the fan speed for a bit so it can shoot the leave out.

 

OK I have it apart. It look like the blend door operates just fine. Its just that when you have the temp selector to cold, you feel the full force of the blower. As soon as you push the temp selector towards cold it opens the other door (where you can see the evaporator) Thats where it the air seems to be held up in. I see this is starting to sound kinda weird but I don't know how else to explain it.