280ZX Climate Control ventilation issue

[Connor280ZX]

For whatever reason, no matter what setting i have set the climate control to, air only blows through the lower vents below the dash. Air does not come out of the vents on the top of the dash, or out of the front of the dash. Any ideas on what the problem might be? Also, it has been this way ever since i purchased my car. Thanks.

[BluDestiny]

I'm guessing you have the auto climate control. Mine was like this, but in addition it was never warm air. Before you start you do know that there is a mess of vacuum tubes that control everything behind the dash. Check the FSM for a diagram of  the ventilation system. That would be a good place to start.

[calvin280zxt]

Rotten vac lines Just fixed my own, except my cruise is only good for cold days now.. Heat goes higher the more gas it gives

[Connor280ZX]

Yes, it is the Auto Climate Control model. Took apart the dash and noticed that there seems to be one large duct that goes to the vents in the front of the dash. It looks like that there are some kind of air direction flaps that control which way the air flows. They are pointing down, directing all air flow to the lower vents. According to the Haynes repair manual these are the "Air-Mix Door" and the "Ventilation Door" as well as the "Bypass Door". BTW, the car currently only has 62,000 original miles, and has been garaged since it was sold.

[calvin280zxt]

Those symptom sound like theres no vacuum id start under the hood, the manual has diagrams. The originals are color coded so you want to map it out and get it working then change the rotten lines out. Its pretty confusing but once you decide which part the "vacuum transducer" etc etc is its not to bad

[Hi Def]

Yeap. It's all in the vacuum lines. I'm replacing mine also right now. I have the same exact problem but I don't have the auto air. Heat only comes out on the floor. It's def a headache.

[Connor280ZX]

Yeah, it turned out to be two vaccum lines that were split at the MasterVac. Cut the split ends off, and hooked it all up, now it works great. Thanks for the help guys!

[FricFrac]

For whatever reason, no matter what setting i have set the climate control to, air only blows through the lower vents below the dash. Air does not come out of the vents on the top of the dash, or out of the front of the dash. Any ideas on what the problem might be? Also, it has been this way ever since i purchased my car. Thanks.

Default "fail mode" is to do this - you're loosing vacuum somewhere.  Do yourself a favor and do it right the first time.  Pull the dash then pull the climate control system right out of the car.  Get the FSM from www.xenons130.com to help guide you through.  Basically you'll be replacing or repairing the vacuum lines.  Most of the time they are hardened around where they mate up to the plug in for the switch, valve, etc.  At the very least cut the 1/2 inch section that is hardened off and put the vacuum line back or better yet replace the line itself.  Check the rotory vacuum switch as it can leak vacuum as well.  You can take the whole assembly apart and clean it at the same time.  I replace a the deteriorated foam with open celled foam strips (picked mine up from Home Depot).  Do the same thing for all the venting while you have the dash off.  You'll find the whole system blows like a hurricane now that it doesn't have 1000 leaks everywhere.  Check the heater core and the vacuum controled heater cock - replace that if you can afford it.  They are getting hard to find and if you plan on keeping the car it's a good piece to have new as it can leak down the road.