03 Silverado AC problem

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  #1  
Old 07-18-06, 04:58 AM
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03 Silverado AC problem

Hey y'all;

My AC doesn't seem to be blowing cold air. I checked and filled the system; it holds pressure, but does not blow cold. It sounds like it is kicking off and on like it's trying to run, but some sensor is kicking off. Ideas? If it's a sensor, what one(s) and where are the located on the truck?

thanks for the help,

Cooter
 
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  #2  
Old 07-18-06, 06:01 AM
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Originally Posted by crazycooter
Hey y'all;
My AC doesn't seem to be blowing cold air. I checked and filled the system; it holds pressure, but does not blow cold. It sounds like it is kicking off and on like it's trying to run, but some sensor is kicking off. Ideas? If it's a sensor, what one(s) and where are the located on the truck?
thanks for the help,
Cooter
Cooter,
You didn't give nearly enough information! To determine what's going on with you’re A/C you need to provide pressure readings both from the high side and low side with the system running. Also needed is the outdoor temperature. The system pressures will vary greatly depending on ambient temperature.

Did you evacuate the system and charge virgin refrigerant into a vacuum? If not, more than likely there is air in the system which will raise your systems pressure as well as raise the vent temperature. How do you know you have the correct charge? Did you weigh it? An overcharge will cause the system to cycle on and off due to high pressures, just as a low charge will cause the system to cycle on and off due to low pressures.

The two sensors that will cause the system to cycle are the "High Pressure Cut Out" switch and the "Cycle" switch. (also known as a Low Pressure Cut Out) Also, a weak clutch coil can cause the system to cycle as well as a clutch that had too wide of a gap.

The High Pressure Cut Out Switch is located on the high pressure side of the system somewhere between the outlet of the compressor and the O-tube. (or other type of metering device depending on your system) The cycle switch is located on the low pressure side of the system and can usually be found on the accumulator. (black or silver can mounted near or on the firewall)
Good luck,
Phil
 
  #3  
Old 07-18-06, 06:55 AM
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Phil;

I didn't want to overstate myself if the aswer was a no-brainer, like make sure the engine is on

The ambient temp is 80, but let me give you a little background first.

When I first got the truck (brandy-new), I was driving to work and turned the AC on. It blew warm at an ambient temp of 75) I found at that time if I shut off the truck, up restarting it I could get the AC to work, hence my thought it may be a switch or solenoid that's cutting out. The truck now is 3 years old and has 34,000 miles, with about 500 hours on the engine.

I'm at work, but when I get home (or at lunch) I'll check the pressure readings and see what it says.

No, I didn't evac the system, as I wanted to see if it was just due to low pressure. I don't believe there are any leaks in the system, so my first thought was to try and charge it to see if it would work, and if not, bleed it and recharge, but if it's a solenoid I'd hate to purge the system when it's only a simple part I should have replaced instead.

Virgin refrigerant? Do you buy that in the automotive lingere section of Wal-Mart?

Thanks,
Cooter

Originally Posted by Philossifer
Cooter,
You didn't give nearly enough information! To determine what's going on with you’re A/C you need to provide pressure readings both from the high side and low side with the system running. Also needed is the outdoor temperature. The system pressures will vary greatly depending on ambient temperature.

Did you evacuate the system and charge virgin refrigerant into a vacuum? If not, more than likely there is air in the system which will raise your systems pressure as well as raise the vent temperature. How do you know you have the correct charge? Did you weigh it? An overcharge will cause the system to cycle on and off due to high pressures, just as a low charge will cause the system to cycle on and off due to low pressures.

The two sensors that will cause the system to cycle are the "High Pressure Cut Out" switch and the "Cycle" switch. (also known as a Low Pressure Cut Out) Also, a weak clutch coil can cause the system to cycle as well as a clutch that had too wide of a gap.

The High Pressure Cut Out Switch is located on the high pressure side of the system somewhere between the outlet of the compressor and the O-tube. (or other type of metering device depending on your system) The cycle switch is located on the low pressure side of the system and can usually be found on the accumulator. (black or silver can mounted near or on the firewall)
Good luck,
Phil
 
  #4  
Old 07-18-06, 01:13 PM
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cooter,
If your A/C is cooling when you first run it and the truck is cold, take a good hard look at the clutch/fan. Personally, if it's got 34,000 miles on it, in terms of A/C, I'd just go ahead and replace it.

When you finally do put the guages on it, watch the high side. If if shoots up real high, real fast and then the compresser cycles off, you're not getting enough air flow over the condensor.

If that happens, then cool the condenser with a garden hose and watch the high side. If it drops like turd, then you can bet your bottom dollar, the clutch/fan is bad.
Good luck,
Phil
 
  #5  
Old 07-18-06, 03:10 PM
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Last edited by mattison; 07-19-06 at 04:47 AM. Reason: Off Topic.
  #6  
Old 07-18-06, 04:16 PM
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Phil;

When you're talking about replacing "it", are your referring to the condenser, the clutch fan, or virgin refrigerant? Slightly different costs

Thanks for the input, I read a non NHTSA TSB from AC delco about the low pressure solenoid. I am going to try your idea in the am, and also their idea of whacking the solenoid to see if I can activate it.

Yes, with the guage on it, it does kick on, runs high (100) and cycles back down to 30. During this small (3 sec) cycle time, the tube going to the condensor does get ice cold, then when heats up when the 3 sec cycle ends.

Oh, and Phil, I appreciate your help. Inappropriate remark removed by davzack

-Cooter

Originally Posted by Philossifer
cooter,
If your A/C is cooling when you first run it and the truck is cold, take a good hard look at the clutch/fan. Personally, if it's got 34,000 miles on it, in terms of A/C, I'd just go ahead and replace it.

When you finally do put the guages on it, watch the high side. If if shoots up real high, real fast and then the compresser cycles off, you're not getting enough air flow over the condensor.

If that happens, then cool the condenser with a garden hose and watch the high side. If it drops like turd, then you can bet your bottom dollar, the clutch/fan is bad.
Good luck,
Phil
 

Last edited by davzack; 07-20-06 at 06:33 AM.
  #7  
Old 07-18-06, 11:30 PM
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Is this not covered by your warrenty?

From your last post, im assuming youre talking about the low side. What are your high side pressures?
 
  #8  
Old 07-19-06, 02:21 AM
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Course it's not covered by warranty, because it ran out 3/36, and the 3 years ran out back in Janurary, not really the time of year you'd expect to use the a/c, especially in the northern climes.

Where do I check the high side pressure?

-C

Originally Posted by zzzz1486
Is this not covered by your warrenty?

From your last post, im assuming youre talking about the low side. What are your high side pressures?
 
  #9  
Old 07-19-06, 04:52 AM
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Sorry guys but we do not offer refrigerant side advise in the forums. Although it's legal "right now" for stores to sell 134A the rules of certification still apply. The site does not want to put itself in a position of giving out information for someone to perform an illegal or dangerous action.
 
  #10  
Old 07-19-06, 05:41 AM
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Originally Posted by mattison
Sorry guys but we do not offer refrigerant side advise in the forums. Although it's legal "right now" for stores to sell 134A the rules of certification still apply. The site does not want to put itself in a position of giving out information for someone to perform an illegal or dangerous action.
mattison,
I will respect your request and not post any more A/C advice. But it's hard to believe there could be any recourse to this site (or the owners of this site) because its members post information about A/C.

There are at least ten other A/C sites on the web that I know of where this type of information flows freely. Some of these sites are run by A/C parts distributors and some are run by individuals. The bottom line is that with a small investment in tools and some basic information, most DIY's can save a ton of money doing their own automotive A/C work.

Did you know there are hundreds of internet websites approved by the EPA where anybody can get a 609 certification to handle refrigerant by simply paying a small fee and answering 25 multiple choice questions?

Again, I will respect your request and not post anymore A/C help on your site; but IMO, it's a big mistake on your part because members from this site can simply do a Google search and find plenty of other sites where they can easily get the information they need to repair their A/C. Why not let them get it here?
Phil
 
  #11  
Old 07-19-06, 09:35 AM
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Phil;

Thanks again for your help. I replaced the solenoid, which currently seems to do the trick, at ambient temps. Course, now our heat wave is over

I agree with you on the position of Q&A for refrigerant. I came here as it's well frequented, but there are many other sites from which you can get data in regards to a/c and r134-a.

In Maine, it's illegal to run a vehicle without a muffler. Does that mean you couldn't tell someone here how to use a hacksaw and a welder to take it out? there has to be limits. Simply putting a caveat on the site that expressly disclaims any liability resulting in inappropriate use of materials posted (contact your atty) would suffice in negating the site's legal recourse should it run afoul due to Darwin's law taking out those in the population who incorrectly follow well-intentioned advice.

-Cooter
Originally Posted by Philossifer
mattison,
I will respect your request and not post any more A/C advice. But it's hard to believe there could be any recourse to this site (or the owners of this site) because its members post information about A/C.

There are at least ten other A/C sites on the web that I know of where this type of information flows freely. Some of these sites are run by A/C parts distributors and some are run by individuals. The bottom line is that with a small investment in tools and some basic information, most DIY's can save a ton of money doing their own automotive A/C work.

Did you know there are hundreds of internet websites approved by the EPA where anybody can get a 609 certification to handle refrigerant by simply paying a small fee and answering 25 multiple choice questions?

Again, I will respect your request and not post anymore A/C help on your site; but IMO, it's a big mistake on your part because members from this site can simply do a Google search and find plenty of other sites where they can easily get the information they need to repair their A/C. Why not let them get it here?
Phil
 
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