A/C Compressor Won't Engage - 1999 Blazer

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May 25, 2019 | 04:36 PM

#11

mickey_bigdaddy

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Quote:

Originally Posted by christine_208

So does replacing the pressure switches on the AC system require removal of the refrigerant? I have a 1999 GM service manual and it makes no note of doing that for the High-Pressure Cut-Out Switch nor for the Pressure Cycling Switch. However for other AC service, such a hose replacement the manual will (not surprisingly) mention recovering all of the refrigerant.

Well there isn’t a schrader valve on the compressor. The high pressure switch is installed with an o-ring directly into the socket on back of the compressor and secured with a snap ring. In the socket, there is a hole on the compressor which I assume Freon/oil flows by so that the high pressure switch can read the pressures. When you remove the high pressure switch on a working system, there is oil in that socket so I assume the system is exposed/opened if that switch is removed. I took my Freon out before I took off the compressor so I am not 100% sure.

Jul 19, 2019 | 08:35 AM

#12

jrm000kc

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Joined: Mar 2016

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I found out the hard way that yes, you need to evacuate your system before pulling the one on the back of the compressor. (After the guy at the parts store said I didn't.)