# air conditioning



## Guest (May 7, 2003)

I have an '87 300zx. I think that the door that switches from hot air to cool air is stuck. All I get is hot air. I have switched out the controls to no avail. I found three plungers under the dash and when I manually push in on one and all it switches from defrost to vent to floor but they do not work otherwise, only defrost. I even get hot air out of the defrost vent when I drive and have nothing turned on. I am told that the "door" that closes off the hot is stuck open. Any suggestions? It was 93 degrees today, the hot air in my face is starting to suck. Thanks people for any help. 

PS: The compressor does come on and cycle but still hot air.


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## Guest (May 7, 2003)

Well, before you get into stuck doors and air delivery... you need to verify that the basic A/C refrigeration system is functioning. Does the compressor run? What are the system pressures? Does the compressor cycle? Do you have temperature differential at the compressor's input and output? If so, give estimate. What is your abient temperature you are conducting these tests?


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## Henry8866 (Apr 11, 2003)

sounds like a vacuum leak. Check all your vacuum lines on the passenger side of the engine. Any cracked or torn line in most of the vacuum lines will cause your AC to only spit out hot air.

OH! I didn't read the last couple sentences of your post correctly. If it's blowing out hot air even when the AC is off then it is definately a vacuum leak!


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## Guest (May 15, 2003)

That is nonsense... the vacuum motors only control the air deflection doors... there is a cable that controls the cold/hot door.



Henry8866 said:


> *Any cracked or torn line in most of the vacuum lines will cause your AC to only spit out hot air.
> *


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## Henry8866 (Apr 11, 2003)

I had this same problem with my 300zx. Any problem with the cooling and heating should be followed up by a vacuum line check first, as that's what's 90% cause for it failing.


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