99 Blazer and we had the AC system checked and serviced by a local garage. They pulled a vacuum, did thier cks and said it was good to charge so I think the system is not leaking anywhere. Was working good for a couple weeks, blowing cold. There were a couple times when we turned the AC on, it would blow hot, and we would cycle the switch on the dash to off and then on again and it would start blowing cold again. Most recently it stopped blowing cold all together. Noticed the compressor was not turning so did some reading and jumped the Low pressure Sensor Connector and the compressor started turning. Replaced the Switch and now the Compressor turns on and off in like 3-5 second intervals. Still blows hot. Any suggestions? I've read about the High Pressure Switch on the Compressor. Should I consider replacing it? My understanding is that the system needs to be evacuated to do so. Is that correct? Any way to test it first? Really don't think the charge has leaked out, especially after the garage did their system cks prior to charging it. Any suggestions would be appreciated. Thanks
Lou

 

No. You have a leak somewhere. VERY unlikely you'd have two out of tolerance switches.
The one you replaced is called the cycling switch. The HP switch rarely if ever set so it wont 'wear'

Note another case on here where vacuum holds fine, pressure leaks down. That's the nature of o-ring sealed system.

 

Sure sounds like you still have a leak to me. If the shop didn't do a pressure test with nitrogen, they really don't know if there are leaks or not. They probably only pulled a vacuum for an hour or so then let it sit under vacuum for another hour and said it's A-okay... That doesn't mean that there aren't leaks.

I wouldn't consider replacing the high pressure switch. I'd really go over the entire system with a UV light and see if you can find the leak..

 

Yeah maybe there is a leak. I suppose because of the intermittent problem initially, and being able to get it to blow cold by merely resetting the AC Switch I was thinking more along the lines of an electrical issue. Switch or something.

 

I'm chasing a leak on my '03. I see dye on the accumulater,but no where else. The dye on the accumulater could be from me injecting it. Is it common for the condenser to leak? I have yet to check due to the difficulty of getting to it. Any help would be helpful!