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Discussion Starter · #1 ·
My A/C has been working off and on but lately not working at all. Today I pulled the vacuum check valve off the intake manifold the removed it from the vacuum line. I could hear the vacuum release, I then re installed it and started the Jeep and A/C works fine. I shut the engine off, restarted it and again the A/C didn't work. Performed the same procedure and it works again. Is that check valve possibly bad????
 

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Discussion Starter · #2 ·
I also just noticed at highway speeds the air stops blowing cold. I checked all of the vacuum lines prior to this problem, I replaced one that had a hole in it. All air blows from all the selections as it is supposed to.
 

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That check valve is a one way valve to maintain vacuum pressure so if it's somewhat bad, it may cause your highway issues of warm air. My guess is there's not enough vacuum pressure to maintain the blend door in position to keep the air cool. (That's just my layman's guess, not Chrysler approved) You can try blowing through it to see if it's only allowing air only in one direction.
 

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Discussion Starter · #4 ·
That check valve is a one way valve to maintain vacuum pressure so if it's somewhat bad, it may cause your highway issues of warm air. My guess is there's not enough vacuum pressure to maintain the blend door in position to keep the air cool. (That's just my layman's guess, not Chrysler approved) You can try blowing through it to see if it's only allowing air only in one direction.
Yeah I tried blowing through it and it only goes the one way. Also to help maybe I should have said that unless I disconnect and reconnect like previously explained the compressor does not even come on like it does after that. I had it at a shop not long ago and the freon level is good with no leaks.
 

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You mean the vacuum line running to the vacuum reservoir?
I guess. I didn't pay much attention to what it went to when I checked for (and found) the cracked line. I was getting not-so-cool air and the air would stop coming out of the dash. It was the line under the battery.
 

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Discussion Starter · #8 ·
I guess. I didn't pay much attention to what it went to when I checked for (and found) the cracked line. I was getting not-so-cool air and the air would stop coming out of the dash. It was the line under the battery.
Ok I just wanted to make sure that was the line you meant. Yeah I have checked that and it's good. My air blows strong out of the vent selection I have it on. I had to replace a different line when I first got it last year that was causing it to go to defrost only after about 40 MPH.
 

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Discussion Starter · #10 ·
Is your freon charge good?
About a month ago when I had it serviced and checked for leaks it was. It will still get ice cold when I remove and re install the check valve as long as it sits at idle. I was thinking maybe I need to check the freon again but I feel certain it's good to go.
 

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About a month ago when I had it serviced and checked for leaks it was. It will still get ice cold when I remove and re install the check valve as long as it sits at idle. I was thinking maybe I need to check the freon again but I feel certain it's good to go.
That's weird....
 

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Discussion Starter · #12 ·
That's weird....
LOL yeah it has me stumped. I normally wouldn't care because its a Jeep. But when I go home on the weekends it's almost a four hour drive and I have an English bulldog who doesn't do so great in the heat.
 

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Discussion Starter · #13 ·
Well it turns out it was low on refrigerant (r 134 a). Sorry if I used the word "freon" before. I know the difference an just use the word as force of habit. Anyways due to lack of funds just bought a can from the gas station for $14 and she is blowing ice cold now.
 

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i'm going to have to check all my A/C stuff as well. Just blows engine heat. Making a 4-5 hour trip to Emerald Isle this month and i have a chow/shepherd mix riding with me. On a side note Sarge, I see you're from Chester. I'm in Prince George right beside Ft. Lee.
 

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Discussion Starter · #15 ·
i'm going to have to check all my A/C stuff as well. Just blows engine heat. Making a 4-5 hour trip to Emerald Isle this month and i have a chow/shepherd mix riding with me. On a side note Sarge, I see you're from Chester. I'm in Prince George right beside Ft. Lee.
Yep I work on FT Lee. PM me your number I will help you with your A/C
 

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Discussion Starter · #16 ·
Ok so right now I'm driving my Jeep and still having the issue of only cold air when engine is not under a heavy strain. I have checked both high side pressure as well as low side and both are in line with the FSM. Any ideas??
 

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Discussion Starter · #20 ·
2000 RPM seems to be the sweet/trouble spot. Much over that and the air gets warm again. Could it be the compressor clutch slipping at higher rpms?
Anybody have experience with this?
 
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