A/C high pressure switch bad?

Tiny
99GTP
  • MEMBER
  • 1999 PONTIAC GRAND PRIX
  • 3.8L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 177,000 MILES
Hello, I am the owner of the car listed above gtp. My A/C was working fine until today when I got in my car and turned my A/C on it blew hot and never got cooled until I started driving. But then I my check engine light came on and I read the code and it said my A/C high pressure switch is too low or too high voltage. I do know that this controls the amount of pressure to let in the compressor before shutting the clutch off. My question is, do I have to evacuate my Freon to replace the switch or does my model vehicle have a shut off when removed?
Wednesday, July 20th, 2022 AT 1:54 PM

4 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
In most cases you will not need to discharge the system because there is a Schrader valve that control the refrigerant when the sensor is removed, but is this valve gets stuck or was forgotten in the manufacturing process it will leak out so chances are you will be okay. Here is the location of the sensor so you can change it out in the diagrams below. I have included both the high and low side sensors, so you don't get them mixed up. The high side is the second one. Check out the diagrams (below). Please let us know if you need anything else to get the problem fixed.
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Thursday, July 21st, 2022 AT 11:18 AM
Tiny
99GTP
  • MEMBER
  • 9 POSTS
Thank you for your reply and input. Now I can change this part with a clear mind, lol! I will be getting the part today. Thank you once again!
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Friday, July 22nd, 2022 AT 7:56 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Please let us know if you need anything else to get the problem fixed. :)
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Friday, July 22nd, 2022 AT 5:49 PM
Tiny
99GTP
  • MEMBER
  • 9 POSTS
Yes sir, will do!
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Friday, July 22nd, 2022 AT 5:59 PM

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