Air conditioning not working

Tiny
DRBUZZ0
  • MEMBER
  • 2001 CHRYSLER SEBRING
Six cylinder front wheel drive automatic 104,000 miles.

I have the Limited Convertible model. Recently I noticed the A/C was not providing any cold air.

I went to my local auto parts store and picked up an air conditioning recharge kit, which has the bottle of refrigerant and a gauge. When I hooked it up and followed the instructions, I found that the needle on the gauge was in the "danger" area really high pressure on the low pressure side of the A/C system. So obviously it was not lacking the refrigerant.

I suspect that maybe the clutch on the compressor is not engaging. I am not sure how to troubleshoot this though.

I did check the relays and they are all fine.

What would be the next step? I want to first figure out whether it is the actual air conditioning system or an electrical problem that is causing it not to kick on.
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Monday, August 30th, 2010 AT 1:25 PM

11 Replies

Tiny
WRENCHTECH
  • EXPERT
Do you have the electrical knowledge and equipment to troubleshoot an electrical circuit by reading a wiring diagram if you had one?
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Monday, August 30th, 2010 AT 1:48 PM
Tiny
DRBUZZ0
  • MEMBER
Yes. I do. I just do not have the wiring diagram so I have no idea where what goes where.

I did some additional investigating today. I found the wire that connects to the compressor clutch and I assume that this is supposed to activate it. When I connect a DMM to it and read the voltage from the wire to the ground, it shows zero. When I turn on the air conditioning, it also shows zero. I would assume it is supposed to be +12 when the AC is on. So I may be narrowing the problem.

I do not want to do anything without knowing that it is not going to cause damage, but I was thinking that perhaps I could figure out if the compressor and clutch are okay by just hooking up a test lead to the plug on the compressor and connecting it directly to +12 volts (with a fuse just in case) and if it causes the compressor to engage and the AC system to kick on, then I will know the problem is not with the compressor.

Is this a good/safe idea?
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Monday, August 30th, 2010 AT 3:51 PM
Tiny
WRENCHTECH
  • EXPERT
Yes, that is fine for checking the compressor. You may find this circuit is a bit more complicated than you may be expecting. This system has a three wire pressure sensor that feeds a varying voltage back to the PCM so it can make decisions on the compressor and cooling fan operation.
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Monday, August 30th, 2010 AT 4:20 PM
Tiny
DRBUZZ0
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Alright. I connected the A/C clutch control to +12 and it seems to have engaged the compressor. The compressor seemed to kick on, and the pressure on the low pressure side of the system went down, although it still stayed pretty damn high. It went from about 110 psi to 80 psi, which is still in the red area of the gauge I have. (Which I admit is not the best piece of equipment, it came with a recharge kit)

Also, I feel no cold air coming out of the vents.

So now I am starting to think maybe there is a blockage? Unless there is a valve or something that is not opening.

Is it possible that the reason the compressor will not engage is that the pressure sensor is sensing that something is blocked or something and that is not allowing it to come on?

Someone told me I should try letting most the refrigerant out of the system and then re-charging it. That does not really seem like such a great idea, but I am not sure. Anyway, it is not the ozone depleting type, so I guess I do not have to feel bad about that if I do.
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Monday, August 30th, 2010 AT 5:51 PM
Tiny
WRENCHTECH
  • EXPERT
If you want my honest opinion, you should not be touching this car at all. Air conditioning diagnosis is a lot harder than everyone thinks and a lot of damage can be done to the system very easily. You do not have the equipment needed to do this. You absolutely cannot diagnose this system with that toy gauge. You need a set of professional gauges that read both high and low side to even get started and then you will need a recovery and recharge station. Even if you had all this, you do not have the basic understanding to recognize a serious problem and that can be dangerous.
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Monday, August 30th, 2010 AT 5:57 PM
Tiny
DRBUZZ0
  • MEMBER
I am sure you are right. I have experience on the electrical side of things, and I was really hoping it would turn out to be a problem with the control interface or a relay somewhere. If it were that, I think I could fix it, but it looks now like it is likely with the A/C system itself.

I am severely underemployed at the moment, so I am not sure that seeing a pro on this will be an option. I may have to wait until spring.

At the moment, if I cannot fix it, it is not getting fixed.

Sorry, that is just the long and short of the economic situation I find myself in.
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Monday, August 30th, 2010 AT 6:06 PM
Tiny
WRENCHTECH
  • EXPERT
If you really understand the electrical, you should at least be able to determine what is preventing it from engaging. I gave you all the diagrams that you need.
Just do not mess with the gas system without help and do not go applying power to something unless you really know what your doing. Those relays are controlled by grounding quad drivers in the PCM and if you mistakenly pump power into them, you will be buying a PCM.
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Monday, August 30th, 2010 AT 6:10 PM
Tiny
DRBUZZ0
  • MEMBER
The problem is that the compressor relay is not getting any power on the common pin. When I turn on the air conditioning, the relay coil is energized and the relay closes (as it should). The no pin connects to the common pin.

The common pin (point 64 in the second diagram) is out. I assume it should be at +12, but it is not.

The obvious problem would be that the fuse labeled 12 is blown. However, as far as I can tell, all the fuses in the PDC are good, unless there is a fuse hidden somewhere.
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Monday, August 30th, 2010 AT 6:55 PM
Tiny
WRENCHTECH
  • EXPERT


http://www.2carpros.com/forum/automotive_pictures/561653_Fuses_01_Sebring_1.jpg

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Monday, August 30th, 2010 AT 7:01 PM
Tiny
DRBUZZ0
  • MEMBER
Well darn! I would have not thought to look at that fuse because it is labeled as being for the radiator fan, I guess it is for both. On closes inspection, the fuse is fine, but when I removed it, the contact points had some corrosion on them.

A quick brush-up with some contact cleaner and reseat the fuse and the air conditioning now kicks on and I can ride cool.

Thanks a million! I thought it was an electrical problem. I did not expect it to be such a simple one.
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Tuesday, August 31st, 2010 AT 12:09 AM
Tiny
WRENCHTECH
  • EXPERT
Glad to hear you got it resolved. Feedback is appreciated.
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Tuesday, August 31st, 2010 AT 4:21 AM

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