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Unread 07-05-2006, 09:08 AM   #1
Chris95GC
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NO A/C please help

I can't get my A/C to run. The compressor kicks on for 1-3 seconds, then turns off. I can get it to stay on by jumping the cycling switch connector from the accumulator. When I do this, the compressor runs, but there is still no cold air. The Low side pipe frosts over very quickly. What could the problem be?

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Unread 07-05-2006, 09:24 AM   #2
wmchurch
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Low on refrigerant if you get no cold air after jumping it. You're not geting hot air (100+deg F) are you, just no cold right?
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Unread 07-05-2006, 11:23 AM   #3
Chris95GC
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not hot air...

the air is about ambient temp, or a little warmer. the coolant pressure is normal when the compressor is running and very high when it is off.
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Unread 07-05-2006, 11:34 AM   #4
wmchurch
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Coolant (radiator) temperature is higher when the compressor is not running? That seems a bit strange. You don't have a refrigeration manifold gauge set do you? It seems like you're low on refrigerant, but it's tough to say with out seeing the system pressures.

Also, what are the specs on your Jeep? Year / Model / Engine.
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Unread 07-05-2006, 04:12 PM   #5
sgarlic
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Low refrigerant. The accumulator shuts off the compressor when it senses too low refrigerant, and cycles it to keep it from seizing.
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Unread 07-05-2006, 05:48 PM   #6
wmchurch
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Quote:
Originally Posted by sgarlic
Low refrigerant. The accumulator shuts off the compressor when it senses too low refrigerant, and cycles it to keep it from seizing.
That's not entirely true; the switch also regulates the temperature of the evaporator to prevent it from freezing over ( > 1-2 deg C ). It's not low refrigerant that causes the switch to open, it's low pressure. However, in this case low refrigerant does seem to be the issue.

It's still best to get a gauge set in there and verify it's not something like super high head pressures or something, but if that's the case usually the high pressure cut off switch would engage at that point, shutting the compressor off again.
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Unread 07-05-2006, 05:50 PM   #7
Chris95GC
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i meant to say

Quote:
Originally Posted by Chris95GC
the air is about ambient temp, or a little warmer. the coolant pressure is normal when the compressor is running and very high when it is off.
I meant to say the refrigerant pressure is normal when the compressor is running, and very high when it is off. I've got a generic guage that came with a refrigerant can.

from what i've been reading, it may be a bad switch or sensor somewhere, or it may be a clogged orafice tube. any other ideas? how would I check these?
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Unread 07-05-2006, 06:04 PM   #8
wmchurch
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Quote:
Originally Posted by Chris95GC
I meant to say the refrigerant pressure is normal when the compressor is running, and very high when it is off.

from what ave been reading, it may be a bad switch or sensor somewhere, or it may be a clogged orifice tube. any other ideas? how would I check these?
Well, clogged orifice tube means trouble so you want to hope that's not the case. Since the A/C is a sealed system usually the only thing that can clog the tube is metal particles from your compressor.

You've found the switch that's being tripped. That switch is in series with the only other switch in the system, meaning that if another switch was causing the problem, jumping the clutch cycle switch still wouldn't work.

There are only two switches in the system, the clutch cycle switch (on the dryer) and the high pressure cut off switch (on the hard lines just after the compressor).

If the clutch cycle switch was deflective you would be able to tell by jumping it, if the A/C cools as normal that was the issue (or low refrigerant). If it doesn't cool as usually it's most likely not defective.

It's probably best to head on over to Auto AC Forum and post in there with your symptoms. Again, with out the pressure readings it's mostly guess work.

My guess is, low refrigerant due to a leak. I would assume the leak would be the evaporator core because that's just what seems to happen to these things. I've replaced mine about a year ago. If you put dye in your system, you can usually smell it in the passenger compartment if it's leaking there. Unfortunately you can't see the dye in there because it's all sealed up.

You can always try adding a can of R-134a and see if it kicks back on again, it'll probably last a week, maybe longer.
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Unread 07-06-2006, 04:39 AM   #9
hiller
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I was having the same trouble. Had it looked at by the dealership about a month ago. Paid $100 to have it checked out and recharged. They found no leaks. Last week it started blowing warm air again. Took it back to the dealership and they found out that the evaporator core was bad. It cost me $830 to have that replaced. They spared me the evac and recharge cost on this round due to my loss of $100 last month.

I am pi$$ed...
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Unread 07-06-2006, 06:47 AM   #10
wmchurch
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Evaporator cores suck. As often as they go bad, you would think they would be easier to replace. I guess they don't plan on anyone having a vehicle longer than 5 years any more, so I guess that's what you get.

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