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?

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

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

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

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

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