The A/C Compressor is not turning on?

Tiny
HD2424
  • MEMBER
  • 2003 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 256,000 MILES
I’m having trouble with the A/C compressor coming on.

I’ve tested low and high side pressure switches and they checked out good.

I can jump compressor at relay, and it comes on, but it has trouble sucking down the Freon then not at all this is while I have compressor jumped at relay and compressor is engaged.

My gauges read low side is high and the high side pressure is low.

It’s a new compressor.

My question is, if pressure switches or okay, why doesn’t compressor continually suck down Freon to get compressor to engage. And if I jump relay why it isn’t sucking down Freon.
Saturday, July 30th, 2022 AT 7:15 PM

13 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,709 POSTS
Hi,

I have a feeling you got a bad compressor. What are the pressures you are seeing on both sides when you have it engaged? Also, take a look through this link and let me know if anything helps:

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Also, here is a link that explains in general how to replace a compressor. Take a look through this to see if anything was missed.

https://www.2carpros.com/articles/replace-air-conditioner-compressor

Let me know.

Joe
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Sunday, July 31st, 2022 AT 12:10 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
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When the low side is high and the high side low it means the compressor is not working. Is it a new compressor, if so which brand? The clutch is engaged, correct? then the pressure should differentiate. Also, when you changed the compressor out were there particles from when the old compressor went bad? If so, you should clean the orifice tube.

This guide can help as well, and there is the orifice tube location in the diagrams below:

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.

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Sunday, July 31st, 2022 AT 12:46 PM
Tiny
HD2424
  • MEMBER
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Densco compressor and yes clutch engages pressure on low side is about 100 psi and pressure on high side is 150 PSI. I know new parts can be bad. Could it be anything else other than compressor?

Thanks for the help.
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Sunday, July 31st, 2022 AT 2:33 PM
Tiny
HD2424
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Also, there were no metal shavings when I took off old compressor.
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Sunday, July 31st, 2022 AT 2:37 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,709 POSTS
Did you add oil to the compressor? Also, no matter what, the low side is too high. But based on outside temp, 150 on the high side may not be off. What was the temp outside when you checked the pressures?

Joe
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Sunday, July 31st, 2022 AT 9:41 PM
Tiny
HD2424
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Yes, I added oil to compressor I wanted to add that I was chasing a leak and electrical problem I’ve got those fixed, but I changed evaporator and compressor I put 2 oz oil in both. Could oil be built up in condenser?
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Sunday, July 31st, 2022 AT 10:35 PM
Tiny
HD2424
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Also, temperature outside was 85 degrees.
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Sunday, July 31st, 2022 AT 10:38 PM
Tiny
HD2424
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  • 191 POSTS
I know the system should have 8 oz. I’m concerned from changing parts there might be too much oil. From residual oil in system. It took me two times to charge the system to find leak then put new parts.
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Sunday, July 31st, 2022 AT 10:41 PM
Tiny
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Do you think if I change compressor, dryer and condenser it should work if I do should I add 2 oz of to each?
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Monday, August 1st, 2022 AT 1:49 AM
Tiny
KEN L
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Yes, let's also remove the orifice tube to change it condition.
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Monday, August 1st, 2022 AT 2:07 PM
Tiny
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Okay, thanks. Once I install parts I’ll let you know what happens.
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Monday, August 1st, 2022 AT 5:40 PM
Tiny
HD2424
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Update: I had a leak fixed but I had jumped the compressor so when I started charging it was leaking out. It burned up the compressor. I confirmed once I checked orifice tube. I took off lines and cleaned got new dryer, condenser, evaporator, compressor. And also got a quality valve for those darn self-sealing cans always had trouble releasing Freon. Got working perfectly.

Thanks for all your help.
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Friday, August 5th, 2022 AT 8:16 AM
Tiny
JACOBANDNICKOLAS
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Hi,

Thank you for the update. I'm glad to hear it's working for you.

Please feel free to come back anytime in the future. You are always welcome here.

Take care and stay cool.

Joe
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Friday, August 5th, 2022 AT 4:55 PM

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