the middle vents only supply air from the ac unit using a separate in dash fan. the floor and defrost vents come only from the heater
well when mine did it was a vacum line but the dash did have to come off
The flap that directs sir to the selected vents is jammed or broken...or the switch that controls it is.
some thing is probley cloging the vents take it appart and ckeck.
Does air come out at defrost vents? Defrost is the default position. Check for a vacuum leak either under the hood or under the dash Check the operation of the vacuum actuated motors under the dash Check the operation of the selector switch
Heat and steam coming from the dash and air vents after replacing the water pump means that a hose is hooked up backwards in the new installation. The heater is actually taking on water when it is supposed to only take on hot air.
Fuel level, heat or air conditioning up, both high and low, high only, floor only. Center vents are for air conditioning output only, no heat. Heat is designed to blow out side and floor vents only. NOT center. Center is only for air conditioning or summer vents.
The a/c - heater controller is out...........
I just had that problem with my 99 Monte Carlo. When I accelerated or went uphill No air would come out of the dash vents. Problem was a Vacuum hose. Cost about $40 to fix.
Hey Brad==That is where it is suppoaed to come from. Incidentally, what kind of car do you have?? Goodluck, Joe
When you switch the control to direct air through the dash vents, the HVAC system redirects airflow away from the defrost vents. The system uses a series of blend doors to control airflow direction, and if the defrost setting is not activated, those doors remain closed, preventing air from flowing through the defrost vents. Therefore, air is channeled exclusively to the dash vents instead.
Check your ductwork under the dash it sounds like it has come loose not a big deal to do.