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Discussion Starter #1
When I turn my AC on Max AC it will blow cold air at my face, but after I get going about 25-30MPH it changes by itself and starts blowing up on the dash just like I turned it over to defrost! but I didnt touch it! then when I slow down and stop, it switches back to blowing in my face. I know the AC doesnt have anything to do with the speed at which I drive but... I mean... what the hell? :shrug
 

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sounds like the vaccuum source is messed up.
is there a severe leak in the circuit for the air vents?
those being more vaccum is prodced at high RPM then when at idle.... atleast more volume...
its hooke dto manifodl vaccum,. did it somehow get switched to ported vaccuum?
 

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Discussion Starter #5
How could I find out? mine works perfectly on normal AC too. But doesnt normal AC continue to pull in outside air where Max AC recirculates the air inside?
 

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Wll according to a friendly ford mechanic whom I took my 94 in for this reason, it appears as though ford put in a valve that will shut down the a/c when more vacumn is needed as in excelarating or conditions where you need more power. My 94 does this but normally when I get to the speed I want to travel at it will then kick back on. Thats what I heard at least and it does make sense for my a/c problem.
 

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Discussion Starter #7
I never switched it to ported vaccume but I can remember about a year and a half ago I found a small vaccume line that was cracked, and when I touched it, it completely broke off. I made a cheap fix and it does not leak, is that what you are talking about?


By the way, that piece hangin off it is just a wire cover if you cant tell, not a piece of the vaccume hose. not sure if that line is the problem area for my AC but Im tryin to narrow what your talkin about.
 

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Basically the technician told me or the sales mamnager that setup my opiontment told me the A/C actaul has some sort of bypass when it need to use all the requied vacumn . Not excacty sure but believe its located closer to the actual a/c compressor.
 

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Discussion Starter #9
But see when I accellerate the AC does not turn off, the volume of air comming out is the same, it only switches vents from the ones in the front to the vent by the windshield. Not a HUGE problem, mostly just anoying on a hot day.
 

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Just a stab in the dark cause I haven't had it checked out, but mine does it too. I think I can here some sort of valve flapping around at times like it's lose...not neccisarily when theres a vacum proble but more like it swings freely and the forward momentum of my vehicle closes it off...:shrug Is this a possibility??
 

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Discussion Starter #11
Yes, I already thought of that but if I had a diagram of the heating/AC system I could make an educated guess, anyone got one? seems I'm not the only one with this problem. :banghead
 

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Well I have the exact problem as you I lose my nice cold a/c blowing in my face and it goes to the defrost position or somwhere other than the front. Thats what the ford mechanic said they do. He has a 94 bronco and had this problem and decided to educate himself on what the heck was wrong and well thats what he found.
 

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Discussion Starter #14
Broke out the trusty Haynes manual but coudn't find anything about this problem.
 

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Discussion Starter #15
Talked to a mechanic, he said its a vaccume leak for sure. Just gotta find out where, chances are, the leak is probably all the same place on our trucks. :toothless
 

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Well I did my search and found this year old thread....

Has this problem been solved? Is it hardware?

or is it unique to each vehicle on which lines are leaking?

Thanks
 

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Lift your hood and look directly to the back left hand side of your engine compartment. There should be a funny looking round vacuum cylinder with one single white vacuum hose going into it. If you run your finger down the white vacuum hose you will probably find that there is small cracks or holes down the top of it. I was able to pull enough out of the protective sleeve to pull back and cut. You can pull the old line out of the little black rubber female connection on the front of the vacuum cylender and push in the piece you just removed the bad spot out of.
Hope this helps.
 

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u guys are using A/C with these gas prices????? throw all ur vacuum equiptment away and roll with the windows down. im not wasting up to 5mpg on a/c.
 
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