A/C Pressure Switch Question
Thread Starter
Drifting
Joined: Jul 2003
Posts: 1,895
Likes: 1
From: Austin tx
St. Jude Donor '09
A/C Pressure Switch Question
Sunday on the way to Starbucks a very loud pop came from the engine bay area and NO MORE COLD AIR from the A/C. But the controls worked and air was still blowing out the vents.
A friend said to check the Pressure Switch due to them being common for blowing before the hose would. How do I check it to find out if it is bad or not?
And where is it located?
Thanks
Ray
A friend said to check the Pressure Switch due to them being common for blowing before the hose would. How do I check it to find out if it is bad or not?
And where is it located?
Thanks
Ray
Pro
Joined: Jun 2005
Posts: 734
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From: Austin TX
I believe we'd have to hook the lowside up to a gauge to see how much pressure is in there. If there's enough pressure then you likely have a blown pressure switch. If there isn't a lot of pressure in there then you are just low on 134a and need to add some and the pressure switch is functioning correctly.
Thread Starter
Drifting
Joined: Jul 2003
Posts: 1,895
Likes: 1
From: Austin tx
St. Jude Donor '09
The car was blowing Ice prior to the loud pop on Sunday. It would freeze someone with it even on low so something had to have happened to allow the freeon just go away.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Theres no way to test a pressure switch because it a transistorized sensor rather than a switch. You can remove the connector and unscrew the switch off the line and replace it with a new one. Theres a schrader valve under the switch that allows you to remove the switch without having to depressurize the system. If you have actually lost freon, it due to the over pressure relief valve thats located on the BACK of the compressor. I have NEVER heard of that pressure switch blowing up or popping!
If that switch was bad or not working, you should have DTC in the DIC. Read and post the DTC.
BC
If that switch was bad or not working, you should have DTC in the DIC. Read and post the DTC.
BC
Team Owner
Joined: May 2001
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Theres no way to test a pressure switch because it a transistorized sensor rather than a switch. You can remove the connector and unscrew the switch off the line and replace it with a new one. Theres a schrader valve under the switch that allows you to remove the switch without having to depressurize the system. If you have actually lost freon, it due to the over pressure relief valve thats located on the BACK of the compressor. I have NEVER heard of that pressure switch blowing up or popping!
If that switch was bad or not working, you should have DTC in the DIC. Read and post the DTC.
BC
If that switch was bad or not working, you should have DTC in the DIC. Read and post the DTC.
BC
I have never heard of a LP switch "blowing up" either. I wonder if a line blew and dumped the freon and he just hasn't found it yet.
Thread Starter
Drifting
Joined: Jul 2003
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From: Austin tx
St. Jude Donor '09
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Cruising
Joined: Nov 2012
Posts: 11
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loud pop
BTW, when that loud pop was heard, there was no evidence of this core leak, at least there was no telltale on the floor of the garage where it was parked. This stuff looks like it would have made a huge mess wherever it leaked out if it happened when stationary as was the case when the pop was heard.
Last edited by MonroviaKnight; Mar 30, 2014 at 03:02 PM.
Heel & Toe
Joined: Apr 2014
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Better hope it wasn't the compressor, last week I went to turn on the ac in my 2000 c5 vert and was blowing warm air ( I had the system filled a month earlier) with my luck it ended up being the compressor and cost me $950 installed for a new gm one. So pray to the Vette Gods that it is an easy/cheap fix
Cruising
Joined: Nov 2012
Posts: 11
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Compressor problem
Better hope it wasn't the compressor, last week I went to turn on the ac in my 2000 c5 vert and was blowing warm air ( I had the system filled a month earlier) with my luck it ended up being the compressor and cost me $950 installed for a new gm one. So pray to the Vette Gods that it is an easy/cheap fix
Drifting
Joined: Sep 2009
Posts: 1,719
Likes: 4
From: cinnaminson n.j.
St. Jude Donor '14
the easiest way to find your answer would be to hook up a set of gauges. If anything blew, the pressure will be "0". If that's the case, add some freon. It should be easy to hear/see where it's leaking.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Marty is SPOT ON in his recommendation for gages!!
Sounds like you may have a clogged orifice restriction tube. The suction side is going LOW and the high side is trying to overcome the clogged tube. When you added MORE R134, the pressure became too great blew the pressure relief valve.
Thats,,,,, why the LOW pressure cut off is used. To protect the system.
If I were you, I would STOP what your doing and get professional help. What ever you do,,, MAKE SURE that who ever repairs it, puts back in the OIL that blew out with the R-134.
Bill
Sounds like you may have a clogged orifice restriction tube. The suction side is going LOW and the high side is trying to overcome the clogged tube. When you added MORE R134, the pressure became too great blew the pressure relief valve.
Thats,,,,, why the LOW pressure cut off is used. To protect the system.
If I were you, I would STOP what your doing and get professional help. What ever you do,,, MAKE SURE that who ever repairs it, puts back in the OIL that blew out with the R-134.
Bill
