Hello

I have a 200 Dodge Dakota sport. I am having a problem with my AC. If you start the truck and set at idle the AC works correctly. It comes out the dash vents. If you start driving it will switch to the defrost vents. If you slow down it goes back the toe dash vents. What could this be.

 

you have a vacume leak. there is a vacume ball (in the shape of a box) that is underneather the plastic thats below widshhield wipers. its there to cole vacume so when the motor comes to zero vacume it still has some. mine leaks and i am left with no heat. because it does the same thing. other then that check all the control vacume lines. because all hte dash dents are controled by vacume


and if you cant figure this out. suggest opening the window and removing the A?C all together and save the gas

 

I will move this to the 2nd Generation Dakota Sub-Forum.

 

There is a vacuum check valve located in the line to the HVAC system to prevent what you have from happening. Not to say you may not have a leak too.

Look by the power booster and follow the smaller vacuum line coming off of it. You'll see the valve in the line, about 6" from the booster. Replace it.