Stuck on defroster

I had a similar problem with my son's 2000 Mustang, air would not blow through the panel vents but it would from the defrost and floor vents. For me it was an easy fix, the vacuum hose from the controller to the panel-defrost vacuum motor was disconnected. We bought the car used and I had hunch it got accidentally disconnected when the previous owner installed the stereo. I started searching around and I found a yellow vacuum hose dangling on the passenger side under the dash. I removed the stereo from the center console and right behind it was the vacuum motor where the hose belonged, I reconnected it and all works fine. I have uploaded a AC/heat vacuum diagram for the 2000 Mustang. All of the hoses are connected to the controller most likely the main vacuum line is disconnected or damaged, meaning there is no vacuum to the controller. The default condition with no vacuum is both the floor and register vent doors are closed forcing the air through the defrost vents.

Here is the vacuum line routing diagrams and two guides that can help us. https://www.2carpros.com/articles/air-vents-stay-in-the-defrost-position and https://www.2carpros.com/articles/car-heater-not-working

Please run down these guides and report back.

Thank you for this post I fixed my heater stupid broken vacuum lines under the hood, easy fix.

swithc is stuck on defrost. cannot change to panel or floor. is this a fuse or vacumm line problem?

That is a lack of vacuum causing that.There should be a vacuum line coming out of the firewall on the passenger side that attaches to the engine

thank you found it under hood Vac line disconnected\
steve

Air Conditioning problem
1995 Ford Mustang 6 cyl Two Wheel Drive Automatic 150k miles

95 mustang Still tring to get air to blow out vents will only blow hot air out the defrost holes... no matter if i put it on vent or AC or heat its the same temp and it comes from the defrost holes

Some one said a check valve was messed up The ford dealer ship does not even list one

Im sure its a Vaccum line any pointers on where to start and even after i get it to blow correctly Im not sure air is gonna work

UPDATE

I checked lines under dash No vac long story short I found the line was broke at the vaccum block I fixxed it and have Vac all the way up to a splitter with a pig tail in it it has the numbers E4ZF-9C915-AA and E0995b there is Vac going in to it but none comeing out and the air still only blows out the defrost found out part is the Vapor Purge soloind does that even have anything to do with AC

Update Number 2

I kept searching for a Vac line found one unhooked that was coming out firewall by the accumlator.... Could not find where it hooks to so I hooked it to the Purge valve line mentioned above.... and the vents started working So Im sure thats the right line

My question now is Where is the correct place to hook the line I know the purge vavle needs to be hooked up and i dont want a vac leak......

Also when car is on max AC it blows cool air not cold anyway to test Ac myself with out putting car in the shop

Ok lets tackle one problem at a time if you don't mind. First here is a pic of how the vacuum is routed for the heating system. Let me know how it goes and we will go from there. Once the heater is fixed then we will move to the A/C problem ok. I also need to know if this is a GT or Cobra or ? as some stuff may be different. Get back to me.

Its a V6 also that doesnt help I need to know where the vaccum line under the hood goes the one that feeds all those lines in the pic

I don't say exactly it just say to manifold vacuum. Meaning that is has contant vacuum. If you don't find one let me know and I will check my 98 and see where it goes.

Thanks for the help but this case can be closed.....

I searched and searched and could not find it I stopped by a AC repairshop I found out I used to go to school with the guy..

He told me teeing in to the line i was borrowing would be fine so I did that

I purchased a can of freon put it in the compressor kept clicking over and over The Ac guy then jummped some plug on the Accumlator and told me that there was a blockage somewhere that it was messed up gonna cost 7 or 8 hundred to fix so I said oh well Winter car lol...


Anyway the air was kinda cool but not real cool the I ran up with a friend that puts in home Ac's he stuck his gauges on the car and said it was still low on freon stick one more can in it so I did

The Ac is now colder than my wifes 2005 dodge lol

Hopefully there is no leak and it holds up



Well next project will be repairing the top it will not go up or down with the button have to do it by hand

Ok he jumped was the low pressure switch you do this when the freon it to low for the system work. Now on to your top. In the under hood fuse relay box there is a fuse style circuit breaker 30 amp labeled S this it to the motor for the top check that first let me know if it is blown. If it blown change it and see if blows again. Also check fuse 1 in the fuse box in the car it should be 15 amp. This is also tied to the parking break switch so let me know what you find and I will look over the wiring diagram for the top and go from there.

Recently I went to turn on my A/C and noticed that it was comming out the defrost vent instead of the dash vents, I tried switching to heater and the same result, nothing I do will make it switch, I was told that it may be the blend door motor but cannot find any diagrams or information about a DIY repair proceedure or diagnostic proceedure to make sure that is what is wrong, any suggestions or information would be greatly appreciated

Ok Thanks for all the help Racefan anyway I know one problem with the top i filled the tank with fluid and it tried to work but i heard fluid shooting out the hose under the rear right back seat panel is busted

So I need to know how to get into it and where to find one anyway

Chilton manuel doest have a section on converts

Hi,Look For A Black Or White Small Vacumn Tubing Going Thru the firewall Near Or around The A/c Pipes,Or heater hoses. If it has This Hose Check At The Intake Manifold That It is Connected and Not leaking Vacumn.Also the problem could be inside at the mode switch.Some fords use Electric Motors to move the blend doors , But I Don't think It's Your car.I believe Yours is vacumn System.Not Electrical.Also Check Near your brake booster For A Small Black box With Different size hoses on it .Make Sure that all of them are connected And not leaking.Some cars also Have a Vacumn Can that holds vacumn ,That Sometimes leaks .


Hope This Helps You,
Good Luck
Edward S.

There isn't a lot of infor on it here either, but Latemodel restoration does have the hose kit. Now it seems that most things pertaining to the pump or pump motor require removing the rear seat to get to. I will do some more digging. Let me know how the battle goes.

Well pulled the rear seat and side panel and try to let it up back once more to see where its leaking for sure and its not the hose at all its the top of the cylander...

Is there a way to repair it or will it have to be replaced all together

Also is it very hard to R &R

I would check out Latemodel restoration they have all these parts for restoring late model mustangs and also check out Mustangs Unlimited both do late model restoration stuff and more. I use both and have done some nice Performance Mods too. From what it say's you remove the motor and cylinder as an assembly then remove the cylinder from the motor.

I found a couple online they are exspensive what makes it worse is the junkyrard cost more than a new one

Yea they are not cheap but who would thougt that a wrecking yard would be more wow thats strange.

The AC works great but only blows from the defrost vents on the dashboard. What is wrong and how can I get the air to come out of the vents??

check for vacuum leak in the lines and around the switch
check vacuum source

[quote:ea3e10e3a4="BMRFIXIT"]check for vacuum leak in the lines and around the switch
check vacuum source[/quote:ea3e10e3a4]



Is this hard to do? How much do you think it would cost to have someone take a look at it?

Open hood and try to locate a disconnected vacuum line
and if you like to have some one to take a look at it for you it shouldn’t take more then an hr top

I had the same problem with my 95. Its skinny plastic hose located at the top right area under the hood. Its the middle hose, I hope your lucky like i was because mine broke at the top in a easy place. The hose goes all the way across the back of the engine into the R.H. fender and then it disappears, so good luck. Its cheap too, I spent 5$ to fix it and it took less than 3 minutes. You can find the hose and the rubber connector @ Pep Boys

My son has a 95 Ford Mustang, when you turn on the air conditioning (or heat for that matter) it blows out the defroster vent by the front windshield. Is there a diverter valve that could be not working? I check the fuses and they are okay. The blower motor is working it just won't blow out the vents on the console.

Hi i have a 97 gt and i just started having this problem as well.....if you figured out the fix please let me know

[quote:a8adbf7ce6="JJVJA"]My son has a 95 Ford Mustang, when you turn on the air conditioning (or heat for that matter) it blows out the defroster vent by the front windshield. Is there a diverter valve that could be not working? I check the fuses and they are okay. The blower motor is working it just won't blow out the vents on the console.[/quote:a8adbf7ce6]

My parents 2001 windstar also blows a/c from the defroster???

TO: All

Could be that the defrost door is binding or a disconnected vacuum hose at the air damper door vacuum control motor or the motor itself.

Good Luck

I have a 1998 Mustang GT, the ventilation selector only puts out defrost air regardless of selector position. In other words, if I select the "floor" position and turn the fan control to high I'm getting air flow out of my defrost vents. Doesn't matter what I select......defrost air only , what could be causing this ? Thanks

Sounds like the vacum actuator is broken or leaking might or might not be controlled by the switch.It could be hooked to the air door by a rod that might have come loose.check there.

Hey there i have a 99 mustang gt and I'm having a problem with my air only blowing out of the defrost and feet vents. I've taken it in to a mechanic and they told me my vac pressure was good and the panel/defrost vacuum control motor needed to be replaced...I was just wondering if anyone knows how to do it as well as a part number for the motor cause I cannot find anything on it. Thanx!

The mode selection is done through a series of air doors that are operated by vacuum. When there is either a partial or total loss of vacuum, the system will default to either defrost or on some vehicles, heat. Acceleration can also have an effect on the doors for the same reason.

Look under the hood for a small black plastic hose coming through the firewall. Follow it to the vacuum source looking for any breaks, cracks or leaks. Also follow any other lines that branch off because they may go to a vacuum reservoir (storage tank) and a leak there will cause the same problem. Using a vacuum gauge to determine if you have full vacuum at any given point is the best way to find it. You can cut into the line anywhere and splice it back together with a piece of vacuum hose. Find the broken line, you found your problem.

My AC is only blowing out of the Defrost vents near the front windshield, not through the main vents no matter what I place the selector knob on, but I can still turn the AC off using that knob, what is the problem?

Maybe lost vacumn source from engine or select switch faulty. Need to pull controler out check for vacumn on black hose.

Heater problem
1996 Ford Mustang 6 cyl Manual 97000 miles

i cant get any air to blow thru the vent or any other posistion except the defrost if i turn the knob to vent it blows thru the defrost how do i fix this

You are looking for a vacuum leak. The vent doors are actuated by vacuum. If there is a leak, it goes to defrost and floor.

Check under the dash for leaks as well as under the hood.

98 mustang heater wont blow in face only at top and feet.

Check for vacuum leaks
start at the source under the hood