First, I would like to thank all the people who have posted solutions to this problem. We recently bought a 2011 Jeep Grand Cherokee Laredo and love it except for this high pitched noise when the AC is on and it is at 1000 - 1200 RPMs - exactly how you have described here. We found your postings and brought them to the dealership and I'm happy to report that the problem is fixed!!!
Here's the story...we brought the car in two weeks ago after the sound got very annoying. We asked the technician to drive with us to ensure that they heard the sound which they confirmed. We also gave him some of the postings here highlighting what seemed to have been the fix.
They kept the car for a week and replaced the Expansion Valve and the A/C Suction and Liquid Line (details below
). At the end of the week they notified us that the car still made the sound, so they took it in for another week. During this past week they contacted Chrysler and were running some tests. After a couple days they called me saying they still aren't sure how to fix it, so I returned to this site to see if there was any additional information regarding a fix. That's when I saw krpatrick's post. I forwarded it to the service adviser and followed up with a phone call. He said they had just heard from Chrysler and were going to test something else and then possibly replace it depending on the results of the test. I asked him to please read my email and if they could try the fix krpatrick noted first. The technician read my email, ordered the parts, installed them, and tested confirming the problem was fixed (details below
)!!!! I'm not sure if it was only the stuff they did the second week or a combination of both, but all I know is that it is now fixed!!! SO I'd like to thank all of you for posting this as it would not be fixed without this site!! Thank you!
Here's the fix that was on our 'invoice':
Not fixed - car still made the sound
- 24352001 Valve, expansion (H-valve) - Replace Front Unit (B)
- 82300101AB *Refrigerant-R134A
- 68079483AA Valve-A/C Expansion
- 24454101 O-ring or gasket - Replace Discharge line to compressor/manifold (B)
- 55038201AD Line - A/C Suction and Liquid
- 1979 A/C Lines replaced the A/C suction and liquid and 1 suction line and Recharge system and verified repair
- 55038201AE Line - A/C suction and liquid
- 55038016AE Line - A/C suction
- 82300101AB - *Refrigerant - R134A