All the other settings work (defrost, bottom) but the vents for the front will not work. The air just goes to the bottom when it is set on front. I have changed out the AC control panel/switch to a few different ones with the same results.

Also, while driving it, I notice when I coast or especially when I hit the brakes (say at 25+ mph), I can feel the air shift to the front vents for a few seconds. When I get back on the throttle or off the brakes, it goes back to the bottom. I realize this has to do with vacuum, so does that tell you anything?

I took the vacuum line that controls the HVAC panel and bypassed the HVAC check valve by routing it directly to a vacuum source on the intake and still not luck. Doing this also bypasses the brake booster check valve (where the vacuum line gets it's vacuum source) so that eliminates that too! This all tells me that it is not a vacuum source issue.

Any suggestions besides pull the dash?

Google "dodge dakota blend door issues" and you might find your issue.

-Jon

Does the car have one of those vacuum reserve ball tanks somewhere..?

It may not be a vacuum thing. It might be the door swinging open and closed under acceleration and braking.

AARCONV: No, but is does use a vacuum actuator to control the door.

stumpy: I thought about that, but I don't believe that to be the case.