Air only comes out of defroster vents?

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Check your vacuum lines in the engine bay, more then likely will be the one that goes from the vac tree to the line that goes into the passenger compartment near the heater core.
 
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Sounds like the selector is bad. Thats the default setting for when they go bad i think. It automatically comes out of the defrost. IIRC the selector is just a variable resistor and if a connection in the resistor is bad it defaults to defrost. Somebody please correct me if im wrong, but i think thats the way gm does it.
 
Sounds like the selector is bad. Thats the default setting for when they go bad i think. It automatically comes out of the defrost. IIRC the selector is just a variable resistor and if a connection in the resistor is bad it defaults to defrost. Somebody please correct me if im wrong, but i think thats the way gm does it.

Selector for 79-04 Mustangs is vacuum operated nothing electronic about it but the lights, and the switch for the a/c.
 
another vote for the dinky line running along the firewall. The lines crack or come apart where the boot attaches.
 
It's really simple actually. Advance auto parts has that hard line in stock, it's usually like 6 bucks for a pretty good length of it. Just about every SN95 Mustang I've owned had this problem when I first bought them!
 
Just figured I'd throw out the info I gathered from fixing my vac line for it. I went ahead and picked up the hard line from Advance, for around 6 bucks as someone else said earlier. I tried using electrical tape, but it didn't solve it, so I used heatshrink which, after burning the hell out of my hands a couple times, worked beautifully. :D
 
A/C vent problem

Hello,

I just had the very same problem with my Mustang A/C. If you only get air through your defrost vents on top of your dash, then here's the problem and how to fix it for under $5. Open the hood and find where your A/c hoses come out of the firewall which should be on the passenger side. They are metal pipes usually and there should be a small black vacuum hose close to them. Follow that from the firewall to the connection in the engine compartment. You'll either see a break in the hose or a pinch. What I did was take the hose off at the connection and cut the rubber cushion cup off at the end. I then took a small drill bit about the size of the hose, but not bigger and screwed it through the cushion cup. Then pushed the black hose back through the cushion cup and re-connected the 2 ends and turned on my car so the engine is running. Then turned on the A/C and it worked perfectly. Thety say to replace the entire hose but a new hose does not have the cushion cup at the end. This is the best way to do it without having to pay a single penny out of pocket. I tore my entire dash apart only to find out what the real problem was. Should only take a few minutes to fix the problem once you locate the vacuum hose.

Let me know if this helps by sending me an email to [email protected]
 
Hello,

I just had the very same problem with my Mustang A/C. If you only get air through your defrost vents on top of your dash, then here's the problem and how to fix it for under $5. Open the hood and find where your A/c hoses come out of the firewall which should be on the passenger side. They are metal pipes usually and there should be a small black vacuum hose close to them. Follow that from the firewall to the connection in the engine compartment. You'll either see a break in the hose or a pinch. What I did was take the hose off at the connection and cut the rubber cushion cup off at the end. I then took a small drill bit about the size of the hose, but not bigger and screwed it through the cushion cup. Then pushed the black hose back through the cushion cup and re-connected the 2 ends and turned on my car so the engine is running. Then turned on the A/C and it worked perfectly. Thety say to replace the entire hose but a new hose does not have the cushion cup at the end. This is the best way to do it without having to pay a single penny out of pocket. I tore my entire dash apart only to find out what the real problem was. Should only take a few minutes to fix the problem once you locate the vacuum hose.

Let me know if this helps by sending me an email to [email protected]

did this and it worked great! thanks for the idea. :flag:
 
so i have a question...my a/c doesnt work right now. is that because of this? it was working before it did this problem. if i fix that vacume line, the a/c will work again?