How to diagnose a Variable Displacement A/C Compressor

Learn how to diagnose a vehicle's A/C system that uses a variable displacement A/C compressor.

[@FisherCatProductions]

Interesting. The best explanation I've heard of the relationship between the gauges and what is actually going on in the system! Thank you.

[@relmdrifter]

Thanks, these are new to me!

[@ohenenorb]

Very good explanation of how the variable displacement compressor works. Question: Is variable displacement compressors used only in a vehicle that has climate control system type of air conditioning?

[@user-si9iy9ch7e]

SCOT , LOVED THE INFO . I HAVE SUBSCIBED AMIGO . MY SON HAS A 2019 IMPALA , I THINK HIS IS RUN BY MODULE . HOW DO YOU TROUBLE SHOOT THAT, MY SMALL SCANNER SAYS CLUCH ON BUT NOT SPINNING AND IT SAYS NO REQUEST ON COMPRSSOR BUT ITS ON AUTO W/DIAL ON LOW . DO YOU HAVE A VID ON THAT SIR ?

[@peterdrury5627]

Hello Professor Pentane. I was surprised to see the duty cycle on the PWM control still around 40% when the A.C. was turned off. Would this not possibly point toward a potential error on the PWM controls, which I would have expected to go to zero? If this is normal, I would hope for some discussion on this in your tutorial. I also noticed that when you initially displayed the compressor, you stated that it was a clutchless compressor. Near the conclusion of your tutorial, you stated that the compressor clutch had disengaged. Is it possible that PWM strategies would differ between the two types?

[@bamwa]

Good video. Can you replace the solenoid only if it is acting up?

[@ProfessorPentane]

On some compressors, yes you can only replace the solenoid. Check for parts available.

[@benjamin-rw8qm]

what speed the blower fan was during this test?

[@ProfessorPentane]

I started off with the blower fan on high and towards the end of the video, I switched to low speed to get the duty cycle of the compressor to drop due to the evaporator getting too cold. Thanks for watching, PP.

[@ungoofaaruregionalhospital5189]

thnks

[@leonelcontreras1851]

What Fluke model is that tester? How do you have it show percentages? I tested mine and it only showed decimals on my percentages.

[@ProfessorPentane]

I use a Fluke 88 that has the HZ option.

[@dangrbitch]

I got an ac with one of those compressors. The system has no leaks and did a full recharge. But it only cools at low rpm like at idle. When I start driving it stops cooling Can that possibly be a simple fix or do I likely need a new compressor?

[@friesy3518]

Did you ever find the answer to this? I'm having a similar problem with mine... It's only cool when sitting at idle. The vent temp gets higher when driving at highway speeds.

[@afeezemokpaire]

​@@friesy3518were you able to fix it