1. Home
  2. Chevrolet Trucks
  3. Strange A/C Problem

Strange A/C Problem

I have a 2002 Suburban LT with the automatic environmental control. On a cold start in the morning or after having the truck parked for hours, the A/C (temp control) cools great. Output temp in the center duct is about 45 deg F. The problem is when I have driven the vehicle and shut it off for about 30 minutes, and then restart, the A/C will not cool. If I fiddle with the controls, shut off the auto A/C for a few minutes, or just drive for about 30 minutes, it will start to cool properly again.

The dealer keeps wanting to work on the A/C system itself, but it cools so well when it wants to, that I think the basic physics package is working fine. I'm thinking control box?, modules?, computer?, whatever?.

Has anyone had a similar problem? Would really like to know where to look, or to be able to talk to the dealer with some knowledge. I put up with letting them change the orifice tube and low pressure switch, which of course, fixed nothing. Problem still exists.

Any help / suggestions greatly appreciated. TIA - HH

Reply to
H.Hatcher
Loading thread data ...

sounds like it could have been the low pressure switch....It could also be the high pressure switch. Sounds like you will have to check it when it fails. It could be so many things it would take a wiring diagram and test light or meter to find it. You are on the right track I think...not the compressor, or ref level, exp tube, ect.

Reply to
ShoeSalesman

I had a similar problem on my '03 Silverado Z71 and the dealer fixed it under warranty. What the paperwork states is: "A/C Pressure Cycle Switch is shorted" They replaced it and recharged the A/C system. That was back in Sept-

2004 and since then I've had a repeat of the symptonms only a few times, so I haven't been back in yet (still under warranty) so eventually I'll have them look at it again, but overall that seemed to resolved the regularly reoccurring issue at the time. Hope that helps.

Kev> H.Hatcher wrote:

Reply to
Kevin Klein

The cycle switch is the low pressure switch.

Reply to
ShoeSalesman

Thanks for the replies. Appreciate the encouragement that I'm on right track. It did work better since the low pressure switch was replaced (only one occurance of problem and then it corrected itself in about 15 minutes). I'm going to see how it does over next several weeks. Then maybe back to dealer with more specific info.

Any other thoughts/suggestions still appreciated. This auto climate system is very complex. Personally I'm still leaning toward the control box being the problem - Computer diagnostics pass, but when the computer itself is lying, then how do you know? HH

Reply to
H.Hatcher

There is a low pressure cutout switch located in the rear head of the compressor. There is a pressure cycling switch located at the service fitting on the accumulator. Both provide freeze protection. The low pressure switch will open and shutdown the system if sensing a low-charge condition. The pressure cycling switch monitors low pressure side pressure as a interpretation of evaporator temperature, this device turns the compressor on and off. These switches are separate entities in different physcial locations in the refrigerant cycling system.

Reply to
Jonny

thats a new one to me, every switch Ive seen on the back of the compressor is either a HIGH pressure cut out or a HIGH TEMP cut out. Where are you from? North pole?

Reply to
ShoeSalesman

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.