AC just quit blowing cold all of the sudden
 

And the compressor doesn't appear to be coming on when I turn the AC on.

Troubleshooting tips?

Worst about all of this is my 2022 C8 Vette was supposed to be here by now. So I've either got to fix this and sell it on my own or take the loss in the form of trading it in. FML

Does the light come on? I mean it sounds like you are going to have to do some multi-meter testing. You checked the fuses already I assume?

Sent from my SM-G975U using Tapatalk

Yes, light comes on and I have checked the fuses.

Replacing the compressor is only $200-300 but I would check for loose wiring first. I think there is only one wire (maybe two) that run to the compressor. Make sure you are getting 12v to it when the switch is on. That should engage the magnetic clutch.

Sent from my SM-G975U using Tapatalk

if the refrigerant pressure is too low the system won't engage.

I'll check this stuff out tomorrow. Thanks!

There is also a secret cheat code to switch it to a diagnostic mode. Look in the service manual for the dual climate control. It's buried in there. Will check back later tonight when I get home.

That would be awesome!

First thing to do is put gauges on it and check pressures. For it to not come on at all it would have to be less than around 5psi on the low side. 2nd you could check to see if you are getting voltage to the clutch/clutch resistance. Once you know those items you will know what part of the system to troubleshoot further.

Alright. Look for the manuals link in my sig. Here's a screenshot of the menu drilled down to the important pages. You'll see what I mean pretty quickly.

Grady's on point. That really is the essential first step.

https://i.imgur.com/PfZb5ty.jpg

https://i.imgur.com/y5kA8KM.png

YIKES! After looking at that post, I'd suggest the humfrz method - take the car into a shop and have them fix the AC.

:sigh:

Don't lie. You already had your mind made up before even reading the thread title.

This happened to me once when the car went in to limp mode due to disconnecting the OFT during operation. Cleared the fault code and AC returned. Maybe check for fault codes?

Pretty much so. For me, AC stuff is NOT a DIY thing. Not much anymore is a DIY thing - :sigh:

Sure it is! I have a vacuum pump and reclamation stuff. It's all about cleanliness and adherence to process. It's easy to rebuild a compressor. One job and the tools pay for themselves.

ran the system check and I got "25". Looking it up now.

Solar sensor. I had to replace that on my wife's Camry. Had to take the whole dash off to get to it.

NVM, it looks like 25 can display if the area is dark. I'm getting 20 and if what I'm reading is right that's supposed to mean no problem....

Maybe so. But, all I know, back in the day, it was easier to fix a faulty car AC - just add more ice - :thumbup:

cheaper than paying my brother a beer and a few slices of pizza? i doubt it.

Well... there's that, I guess.

The service manifold and gauge kit can be rented but the Harbor Freight version is perfectly ok. Can't beat it for 60 bucks.
https://www.harborfreight.com/automo...set-58776.html

Hey bro , let me give you a few words of advice .im a ASE MASTER TECH and TOYOTA MASTER TECH for nearly three decades . DTC 25 is stored unless you are in DIRECT sunlight (sun load sensor ) . DTC 20 simply indicates diagnostic check is completed . You won't find a DTC for compressor operation as that HVAC Check is intended to start diagnosis of air distribution ,recirculation, auto functions and blend mechanisms . So try this -

1) gauges are preferred but in a pinch you can put some gloves on and safety glasses ...take off either service cap ....using a golf tee or chopstick or similar item carefully and quickly depress the schraeder valve in the center of service port ....if you get ANY blast of pressure ,this would indicate enough refrigerant to close low pressure switch and your system is "full enough" to allow compressor operation . IF NOT - as in almost no pressure - your system is empty and you need to find the leak source . Look for oily dust around components in AC system including hose crimps and all components ( refrigerant carries oil within the system so when it leaks it's usually fairly easy to inspect visually since you probably don't have an electronic leak detector or black light )

Low system pressure will not allow compressor operation by opening the relay control circuit to ground.

2) using a test light hooked to a solid ground or negative battery terminal , probe compressor mag clutch power feed wire when AC is switched on and blower is operating - if you have 11 volts or above , then the problem is compressor clutch field coil ( which I would suggest complete compressor Assy)

3) if no power on feed wire to mag clutch under same conditions as above - you would move over to the AC mag clutch relay underhood and tap on it , squeeze it ,etc. ( AC SWITCHED ON ) . If it engages , the relay has failed which is fairly common .

4) also at that time , find another relay in the box like horn or cooling fan that is the same style and swap them .if compressor operates go buy a new relay ( make sure you get dealer or at least DENSO)

Get that far and let me know , I'll do the best I can to guide you thru remotely .

I had the same symptoms, o rings lines was replaced.

@ Blackmetal. Thanks, I'll check it out this weekend. I found that note in the service manual about the 25 code and it did go away when I pulled the car outside.

I'll try and locate #1 and #2 this weekend.

There's a hole in the actual compressor. But good news is I got a build date of April 24th so I'll have it by April 1st and I won't be worrying about this. :)

Well that's probably the problem right there!

Sent from my SM-G975U using Tapatalk

Someone else's problem in a few weeks. ;)

Wait... we went through all this before you lifted your hood? :slap:

Also, wow. While conceivable, I've never heard of a modern compressor fragging until now.

I did. Put a multi meter on the plug as well. Service rep said no way anyone could see it with the neked eye. It was very faint.

Good news guys I'll ha e a few parts to sell soon lol

If anyone comes across this thread looking for information regarding the Heater Relay which was not the issue here but listed as a possible cause. I ran into this issue awhile back where the compressor would not engage and swapped the Horn relay in for the Heater relay. Spent some time searching for the replacement only for subaru to list it as discontinued. but I have now found out that they stock it for other models under part number: 82501AG041

On a separate note, are you going to daily a C8? What's your commute like?

Curious how a car like that lasts and behaves as a daily

I do plan on driving it on the reg. We also have a new GX460 that we'll take on trips, when we want to take the dogs somewhere or want to ride with more than just us lol.

I never understood the idea of not driving a new car. I can see if it's highly tuned and just that impractical or whatever. But not driving a car to keep the mileage low for resale is like not banging your GF so she's not worn out for the next guy.

I’ve got an AC issue as well.
Don’t want to start a new threat, but I will if I need to.
2017. Pressure in the system. Sprays when shrader valves are depressed. Compressor kicks on. Clutch locks up and spins. Line into condenser is hot. Line out is cold. Module on firewall is very cold. No cold air in cabin. Brand new cabin air filter. Still no bueno.

It's prohibited to vent r134a, and yes I'm pissy about it because we have to go through certifications for this stuff while any schmuck can just press on the valves lol. I would have helped but you're on your own.

If it's not just hot air, over pressured system or blockage.

I just vented the whole thing to atmosphere. I’ll refill it tomorrow and try again.

Sure.

Sounded like an easy issue, have fun with it. You're clearly on the right track so it should all be sorted in a snap.

Got a bunch of 134a on my last trip south. Plenty to blow around.

Maybe make another thread @Tokay444 because you went and trolled rznt4r :lol: