No air coming out of the dashboard vents

[Alien10]

Hoping someone can help. I have an 86 GT 5.0. When I turn the vent fan on I hear the fan running, however no air comes out of any of the vents. I dont have the AC hooked up and was wondering if that could be part of the reason. If not do I need to remove the dashboard to see if any of the vent tubes arnt lined up or something?

[84specialed]

all that stuff works off of engine vacuum. i would start looking for a vacuum leak under the hood around the passenger side of the firewall. It should have some hard plastic vacuum lines, when they get old and brittle they're easy to break. hope this helps.

[netminda85]

I ran into this just a few months back...the only difference is that my AC does work. I first did what 84specialed suggested and confirmed that I had vaccum to the firewall. Ended up being an issue with the arm that open and closed the vent door. Unforunately the dash had to come apart to get to it. Works great now, but it was a major PITA!

Rob

[netminda85]

Here is the link to my thread on this issue:

http://vb.foureyedpride.com/showthread.php?t=133655

[Alien10]

Thanks everyone for your help, I guess I'll be removing the dashboard this weekend

[JACook]

Really? Without any diagnosis first? Just 'cause that fixed it for one person, doesn't mean
you have the same problem. Have you verified no leaks in the vacuum feed to the system?
Without vacuum, the system will always default to the defrost position.

Every one of the servos can be tested, some without removing anything, others you pull the
control pod out to get to the lines. But the very first thing to check is the system vacuum feed.
It's a very common failure point, way moreso than servo failure.

[lilpanther]

Mine had this issue. The cable attached to the lever wasn't in its slot on the control panel. Fixed it without removing the dash.

[JACook]

On an A/C system, unlike cars that only have heaters, the only thing that's controlled
by a cable is the heat blend door. Everything else is controlled by vacuum.

[83_GT_Conv]

Im also in the same boat, my non-AC '83 only blows heat out by the feet, I dont feel anything out of the dash vents. I dont believe I have any vaccume leaks (checked this when my car wouldnt stay running).

Anyone have any ideas?

[JACook]

The non-AC system does not use vacuum controls. Everything is operated by a pair of cables.

The early '83 system gives you the choice of floor, defrost, or a mix of the two. Mid-'83 added
the "panel" position, to blow air out the dash vents.

[k98dave]

You should be able to get to the cable to adjust by removing just the glove box door and not the dash

[83_GT_Conv]

The non-AC system does not use vacuum controls. Everything is operated by a pair of cables.

The early '83 system gives you the choice of floor, defrost, or a mix of the two. Mid-'83 added
the "panel" position, to blow air out the dash vents.

Ahh I see, so just to be clear... me only having the defrost and the feet blowing is working just how its supposed to be?

[Matt J]

Thanks everyone for your help, I guess I'll be removing the dashboard this weekend

To add on to what Jeff said, do you have air coming out of the defrost vents? You mentioned no air coming out of any vents at all...if it's coming out of the defrost, then you know the fan is actually working alright, and it's a duct control issue. If no air is coming out of there, then it's likely something else. You can push the little door for the AC vent under the glove box with a screwdriver or your finger if feeling bold while the fan is on to be sure it's actually turning. I had a mouse set up a home in my heater box right in front of the heater core that actually blocked the air flow completely. I'd guess it's something simple, try the easy stuff first. Pulling the dash in that car with AC sucks. It's not a complicated job, and there's some great step by step references available on this site, but it's a bear of a job.

I hope it's something easy!

[k98dave]

Ditto what 84special said in the 2nd reply. When air only comes out of the defroster that is a sign that the vaccum supply which is a small hard plastic line that passes thru the firewall on the passenger side is either broken or leaking. My Ford shop manual states this is the default mode. I had this happen on several of my cars over the years. These lines can be repaired with 1/8" Id rubber hose available in most part stores. I would check this line in the engine compartment and where it comes thru behind the glove box before you start pulling the dash.