QuestionMy ac is blowing hot air. I took it to a shop who did a recharge but said it keeps blowing hot air. He said that he couldn't hear the compressor switch turn on so he discharged it and recommended me to a shop that could do a more thorough diagnostic test on the compressor. One shop says it needs to be recharged to test it. Is this true? What exactly do they do in this test? How much would a new switch cost to replace? Does Chevy have a lot of problems with their AC compressors?
AnswerHello Christine,
I hope he didn't charge you for his work or freon.
Yes, it needs to be charged to check the switch and compressor. but it does NOT need to be discharged to replace the switch.
Testing the pressure switch? First you need to know what it is.
it is a switch that will open if there is not enough pressure on the low side, meaning there is not enough freon in the system. The switch will open to keep the compressor from damaging itself.
If a tech knows there is enough pressure that the compressor should be running, he will check for voltage to the switch, and then to the compressor.
Bypassing the switch to see if the compressor is good is quite simple, and he will do that.
The compressor itself can be operated with jumpers to see if the clutch coil is good, and if the compressor is good.
Apparently, the first shop knows nothing about air conditioners, except how to add freon.
New pressure switch costs about $15. I think, and just a few minutes to replace.
But there are several other things that could cause it to not work. A blown fuse is one of them.
And you might have had a correct charge of freon in the first place. Hope that guy didn't take all your freon with his.
Make sure you tell the other shop that he discharged it, so they don't spend a lot of time searching for a leak that may not be there.
Good luck,
Van
