Air Condition not blowing cold

Tiny
CIPRIMM23
  • MEMBER
  • 2007 DODGE NITRO
  • 4.3L
  • V6
  • 4WD
  • AUTOMATIC
  • 115,000 MILES
My air conditioner has been working fine. However this afternoon I noticed when driving it that the air conditioner was not blowing COLD air. It was cool but not cold. I turned the air conditioner to the maximum setting and turned the re circ. Fan on. It blew harder but still not cold. Once I got home, I checked the compressor under the hood and it was cycling like it should. No leaks have been detected. Where do I start?
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Tuesday, May 6th, 2014 AT 2:45 PM

22 Replies

Tiny
HMAC300
  • EXPERT
It sounds like the system is low on charge, Here are a couple of guides that will help you find out what the problem is.

https://www.2carpros.com/articles/air-conditioner-leak-detection

and

https://www.2carpros.com/articles/air-conditioner-how-to-add-freon

Let us know how is goes so it will help others
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Tuesday, May 6th, 2014 AT 3:18 PM
Tiny
CIPRIMM23
  • MEMBER
  • 2007 DODGE NITRO
  • V6
  • 4WD
  • AUTOMATIC
  • 140,000 MILES
A few days ago my car stopped blowing air out of the vents unless it was on the maximum setting. I changed the blower motor resistor and it fixed the issue. Now, the air that blows out the vents is warm when the A/C is on. Not heater air but more ambient temperature air. At times the compressor is not running at all and of course the air is warmer. Other times it kicks on and the air is slightly cooler but not A/C air still. The system was recharged last year and we have not had an issue until now. I did stop by the part store and pick up a can of R134. When I hooked the gauge up to the port, it showed all the way in the red. Per the can, it says do not attempt to fill if the compressor is on and it reads in the red. I stopped what I was doing at that point and am looking for answers. I did smell a slight burning smell similar to that of burning brakes. Any help is appreciated!
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Sunday, July 14th, 2019 AT 12:48 PM (Merged)
Tiny
STEVE W.
  • EXPERT
You need to put a real gauge set on there and actually look at low and high side pressures. Once you verify that you have a place to start from. At the moment you do not know for sure it has a charge. The other issue with warm air could be a bad blend door but I would get the A/C working first as it makes it easier to test the blend door.
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Sunday, July 14th, 2019 AT 12:48 PM (Merged)
Tiny
CIPRIMM23
  • MEMBER
Okay, I will see if I can get my hands on a set. I have never used the big sets before but it should be pretty easy. Not sure if it matters, but removing the gauge chuck off of the low side I could feel decent pressure behind it. Any concern with the smell? Or still start with good gauges?
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Sunday, July 14th, 2019 AT 12:48 PM (Merged)
Tiny
STEVE W.
  • EXPERT
Start with the gauges. That way you know if the system has a charge, then you can diagnose the rest of the system.
The smell could be a couple things, one, blower motor is starting to fail. That would increase the current across the blower resistor which caused the old one to fail. Or it could be the clutch on the compressor failing.
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Sunday, July 14th, 2019 AT 12:48 PM (Merged)
Tiny
HAMBONE887
  • MEMBER
  • 2007 DODGE NITRO
  • 75,000 MILES
Hello my AC is not working thinking it might have been something I did I added some freon last week to my a/c I overcharged a little bit about 10psi I let the freon out through the Lo port with pliers I know illegal right anyways it worked fine after that then when went up to the mountains and as we were climbing the A/C went from cold to hot quickly.I checked the lo port when we got back and know its reading relly high and if I let some pressure out it quickly builds up to around the 80-90 psi range any help or thoughts on this would be appreciated thanks, Eric
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Sunday, July 14th, 2019 AT 12:48 PM (Merged)
Tiny
CARADIODOC
  • EXPERT
Before you do anything else, you need to understand how refrigerant works. You have some other problem causing the system to turn off as a safeguard. When that happens, the high and low side pressures will equalize so the low side is going to read too high, compared to when the system is running. If you bleed some off thinking you're going to lower the pressure, it's not going to happen. The lower pressure will just allow more of the liquid in the system to vaporize and expand, and that will make the pressure go right back up. The pressure in the system will be proportional to the outside air temperature. As you bleed more off, more liquid will vaporize and expand and the pressure will go back up. It will keep on doing that as long as there is still some liquid left to vaporize. Once that point is reached, it will be like a car tire. The more you bleed, the lower the pressure will go. Air in a tire is already fully vaporized so there's nothing in there to expand when you bleed some off.

Also, there is absolutely no way to know how fully charged the system is except by recovering the full amount, pumping the system into a vacuum, then injecting a measured amount. Because of the way refrigerant acts under pressure, reading the high and low side pressures with the system not running is meaningless. Experienced AC mechanics can tell from the pressures how the system is performing when it's running, but even they can't tell if it's slightly over or undercharged.
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Sunday, July 14th, 2019 AT 12:48 PM (Merged)
Tiny
HAMBONE887
  • MEMBER
That actually makes alot of sense now I took it to a meinike I saw a sign for free AC check and the guy there looked it over pumped some froen in there and said my limit switch I guess didn't turn the compressor off and burned it up prolly when I was climbing the mountain any thoughts on that
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Sunday, July 14th, 2019 AT 12:48 PM (Merged)
Tiny
CARADIODOC
  • EXPERT
I suspect he's guessing. I don't know which system your vehicle uses but regardless, there's a pressure relief valve in the receiver-drier that would have blown off if too much pressure built up.

Starting somewhere in the mid '90s on some models, Chrysler started using compressors with a variable "wobble plate". It self adjusts according to the low side pressure. When there's more heat load, the pressure goes up due to a rise in the refrigerant's temperature as it leaves the evaporator in the dash. That higher pressure adjusts the wobble plate to make the pistons take longer strokes and pump more refrigerant. That way the compressor doesn't have to regulate by turning on and off. That can be felt and can be annoying.

The other system uses an expansion valve, often called the "H valve". It is a controlled leak that is adjusted by a gas in a sensing bulb on the evaporator that expands when it warms up, and that expanded gas pushes on the expansion valve to open up and let more refrigerant in. Those H valves caused a lot of trouble but they usually got handled when the vehicle was still in warranty. Depending on how they stuck, the valve would not let enough refrigerant through to cool the air or it would let too much through. Then the evaporator would drop below 32 degrees and the condensed humidity would freeze into a block of ice that blocked air flow.

I don't like to argue with a mechanic over something I can't see or diagnose myself, but I'm not sure I follow his reasoning. I find it hard to believe something else in the system is going to damage the compressor. If it is just the clutch that has failed, that is not uncommon. They seemed to have a lot of clutch coil trouble starting around the late '90s to 2000. It's a Japanese part so you'd expect to find better quality, but failure is common.
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Sunday, July 14th, 2019 AT 12:48 PM (Merged)
Tiny
COMPRESS4AC
  • MEMBER
  • 2007 DODGE NITRO
  • 3.7L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 98,000 MILES
Can the a/c compressor clutch in this car be jump started
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Sunday, July 14th, 2019 AT 12:48 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
You can run power directly to it to see if it turns on. However, if it isn't working automatically, something is causing a problem. It could be low Freon, a cycle switch, bad compressor clutch.
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Sunday, July 14th, 2019 AT 12:48 PM (Merged)
Tiny
CIPRIMM23
  • MEMBER
  • 2007 DODGE NITRO
  • V6
  • 4WD
  • AUTOMATIC
  • 120,000 MILES
Where in the world is the AC Drier! I've traced the lines from the top and bottom and can't find any clue of the drier. I've found the x valve, ac compressor, high and low side. No drier. Getting ready to replace the ac compressor because it is out, and would like to change the drier also. Or is it even necessary? Any help would be appreciated. If your able to find a diagram that would be great also. Thank you.
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Sunday, July 14th, 2019 AT 12:48 PM (Merged)
Tiny
HMAC300
  • EXPERT
It's also called an accumaltor which normally is connected to the evaporator at firewall. Yours however is by the condenser make sure ot replace drier as well as expansion orfice and that there is no junk in system otherwise your system won't work to well if at all.
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Sunday, July 14th, 2019 AT 12:48 PM (Merged)
Tiny
CIPRIMM23
  • MEMBER
The diagram helps. Im used to seeing them sitting up pretty in plane view. Any recommendations on how to get to it? Don't want to have to take the grill out. I looked in that location but it didn't stick out, so Ill have to look again. Is it necessary to totally vacuum down the system? Or could I get away with just 'bleeding' the lines? I read on a forum that dealerships just unhook the old, re connect the new, then top it off with freon. Doesn't sound too smart to me, but do you think that would work?
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Sunday, July 14th, 2019 AT 12:48 PM (Merged)
Tiny
HMAC300
  • EXPERT
Anytime a system is opened up it should be vacuumed down just blocking it off and replacing the part then refilling is not good. I can't copy the instructions but the grill has to come out an dyou have to remove the bolt from under the fascia once you unhook the lines if the system hasn't been pumped down or Freon removed it will blow all over an dyou will need to add oil as well.
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Sunday, July 14th, 2019 AT 12:48 PM (Merged)
Tiny
CIPRIMM23
  • MEMBER
Ok. I think Ill just buy the whole kit. Might as well do it the right way. I found a video for grille removal. Seems pretty straight forward. I really appreciate your help. Hopefully I can get this done without too much pain.
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Sunday, July 14th, 2019 AT 12:48 PM (Merged)
Tiny
FORTECARL
  • MEMBER
  • 2007 DODGE NITRO
  • 3.7L
  • V6
  • 4WD
  • AUTOMATIC
  • 125,000 MILES
Can not find the lowside port for charging the air conditioner
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Sunday, July 14th, 2019 AT 12:48 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
Two lines come from the compressor. One is hose larger than the other in diameter. The low side port will be on the larger line here are two videos that will help

https://youtu.be/ON2dYcmXIAw

and

https://youtu.be/uZrQCGwXfek

Please run down these videos and report back if needed

Cheers
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Sunday, July 14th, 2019 AT 12:49 PM (Merged)
Tiny
JANABRUCE
  • MEMBER
  • 2007 DODGE NITRO
  • 3.7L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 113,000 MILES
I am trying to put R34a in my Nitro because the air is not cold. Which on is the low pressure port that you put this in there is one port by the front left side and one port closer to the back middle under the hood?
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Sunday, July 14th, 2019 AT 12:49 PM (Merged)
Tiny
WRENCHTECH
  • EXPERT
Hello,

The low side port is on the larger AC tubes coming from the firewall and headed tot he compressor here is a guide t help you get the job done and the location of the charge port below.

https://www.2carpros.com/articles/air-conditioner-how-to-add-freon

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

Cheers
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Sunday, July 14th, 2019 AT 12:49 PM (Merged)

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