Defroster is the only place heat is coming from

[writchotte]

Please tell me why I can no longer push my various heater buttons and get the heater to come out the vents or onto the floor.
1. What could it be?
2. How much work is it to fix you think?

 

[MonsterMark]

What year car do you have?

 

[ERIC1]

b l e n d d o o r. thats how mine started out

 

[writchotte]

What does your post mean please?

b l e n d d o o r. thats how mine started out

What is blendoor?

 

[MonsterMark]

What is blendoor?

Blend Door. Part of the heating/air conditioning unit that proportions hot and cold. Again, what year is your car? We need to know that in order to help you out.

 

[Markviiiedrea]

im thinking mine needs a blend door finally, when i start my car the temp comes out what is programed but after 20 min if i want to get any heat i have to have it at 90 other wis cold air comes out no matter what the temp is in or out side the car.

Eric

 

[writchotte]

My car is a 1993 Mark VIII

The is plenty of heat and setting the temperature works just fine. It is only coming out the defroster.

 

[MonsterMark]

Then I would probably say the head unit in the dash may be going capute. Maybe someone else will chime in with a more definitive answer.

 

[PioneerCrazed]

Does this only happen on heat, or both heat and A/C? Have you messed the any of the system lately? If you put it on MAX, Automatic, or DEF, will it always come out of the defroster? I have a 94 and this happened to me also, with both heat and A/C only coming out of the floor or the defroster. The reason for mine is when I changed over to a unit from a 96 with the upgraded buttons I detached a vacuum hose. This could also be your problem.

 

[scott9050]

The reason for mine is when I changed over to a unit from a 96 with the upgraded buttons I detached a vacuum hose. This could also be your problem.

I would agree with this, I have had it happen on several cars after stereo installs.

 

[79ford]

Tahe same thing happend to my 97 mark VIII and I found a vacuum leak on the fire wall on the passenger side of the car. It was a red vacuum hose that was cracked. You can hear it when the car is running. Try that.

 

[l-m tech]

defrost the failure position so that the windsheild dosnt fog or frost over.either you have lost vac.the door tthat controls air flow position,the actuator that operates that door and cotrol head.you can put your system through self diag to generate a fault code.