No heat - ac stays on blowing through defrost vents

If the air flow cannot be controlled from vent/defrost/floor you may have a blend door issue. This is an electric motor that operates a door in the heating system to control airflow. There are usually 3 motors controlling airflow direction,heat and recirculation. The Ac not blowing cold may also be another problem. If the AC is operational, the compressor will be engaged and the Ac low pressure line under the hood will bw cold. If this is all ok then a blend door issue should be suspected

On the motorcraft parts web site, you can blow up
a picture of the HVAC Blend Door Motors & locations,
as well as part numbers

You can get failed motor from Amazon

With knowing where the motors are located, try switching
the air flow modes manually, to see what positions do not work

Then you know what motors to replace

I also have professional scan tool software & can see the codes
for the motors in enhanced data.

The-- Vent Blend Doors-by name

Defrost-up top
Cabin -the vents as you say in the middle & on the sides
Floor
Recirculate-under the glove box
Blend Door -under the dash on your print

Check the fan/fans to see if they are working and the fuses. These are the usual causes of a bad vent

If both heater hoses are hot, and the radiator is full of coolant, it may be a blend door problem under the dash.
The blend doors direct air thru the heater core and out thru the vents.
It may still be under Ford warranty.

For some reason this question was listed a dozen times within an hour or so.
Usually the problem is a blend door under the dash. The blend doors direct air thru the heater core and the vents.

You likely have a faulty blend door. It could be electrically, mechanically related, or even a broken door. It may be the blend door motor, or possibly the temp sensor.

the heater vacuum motor and lines needs to be checked.Also get the blend door checked.

NO HEAT ON FLOOR VENTS

---------

As per your problem mentioned. There are few solved help links to troubleshoot these problems. Go through the list and Click the link below:----

2000 Toyota Avalon: No heat on Passenger Side?

http://whatisbyme.blogspot.in/2012/05/2000-toyota-avalon-no-heat-on-passenger.html

------------

No heat on Oldsmobile Silhouette?

http://technoanswers.blogspot.in/2012/02/no-heat-on-oldsmobile-silhouette.html

------------

Heater blows cold?

http://schematicsdiagram.blogspot.in/2012/02/heater-blows-cold.html

-----------

Heat blows cold on drivers side and hot on passenger side?

http://schematicsdiagram.blogspot.com/2011/12/heat-blows-cold-on-drivers-side-and-hot.html

----------

Hot air on the driver's side vents only?

http://repairhelpcenter.blogspot.com/2012/01/hot-air-on-drivers-side-vents-only.html

--------------

Temperature gauge does not move and no heat when heater is ON?

http://technoanswers.blogspot.com/2012/01/temperature-gauge-does-not-move-and-no.html

-----------

1992 Toyota Camry: A/C Control light Flashing and A/C not Blowing Cold?

http://technoanswers.blogspot.in/2012/04/1992-toyota-camry-ac-control-light.html

--------------

No heat, blower blows only cold?

http://technoanswers.blogspot.in/2012/02/no-heatblower-blows-only-cold.html

----------

Ford F150 Ac only blows through defrost vents?

http://technoanswers.blogspot.com/2012/01/forf-f150-ac-only-blows-through-defrost.html

----------

Dodge A/C come out of defrost vents only?

http://technoanswers.blogspot.com/2012/01/dodge-ac-come-out-of-defrost-vents-only.html

---------

Ac vacuum line on dodge cummins?

http://technoanswers.blogspot.com/2012/01/ac-vacuum-line-on-dodge-cummins.html

---------

Ford ranger AC blows cold through defrost vents instead on cabin vents?

http://technoanswers.blogspot.com/2012/01/ford-ranger-ac-blows-cold-through.html

----------

2005 Chrysler PT Cruiser: A/C Blows Warm?

http://whoisbyme.blogspot.in/2012/06/2005-chrysler-p8t-cruiser-ac-blows-warm.html

-------------

2009 Mercury Grand Marquis: A/C blows Cold From Defrost Vent Only?

http://whoisbyme.blogspot.in/2012/06/2009-mercury-grand-marquis-ac-blows.html

-----------

AC not blowing through Vents on 2007 Chevy Trailblazer?

http://schematicsdiagram.blogspot.in/2012/04/ac-not-blowing-through-vents-on-2007.html

----------

Passenger side temperature is warm air out of dash vents?

http://schematicsdiagram.blogspot.in/2012/04/passenger-side-temperature-is-warm-air.html

----------

These will help.

Thanks.

Sounds like a blend door problem. The vacuum from the engine opens and closes the door that directs air flow thru the vents.
I would guess the door is stuck in the middle of the range or something is blocking it.
The blend door(s) is behind the glove box.

Sounds like you have a problem with your blend door in your air distribution box behind the dash. Somebody needs to get in there and figure out why it won't switch from defrost to the vents or floor setting.

check or loss of vacuum to mode control switch in dash ac control. these are not blend doors, they are air flow control, a blend door controls the air temperature not where it comes out.