[unostang]

The rear AC in my 2019 Enclave was not blowing cold air, I’d say cool at best. I did some trouble shooting and it seems that with the rear AC on low, and the drivers AC on low, it causes the rear to blow warm. If I increase the drivers temp to 65F, the rear will be noticeable colder. Has anyone run into this issue? How would the drivers side ac have any effect on the rear temp? Passenger is cold as ice and has no effect on either drivers or rear temps when increasing or decreasing that zone’s temperatures.

 

[Alvenir]

If you have set the front that cold (below 65), it is probably directing most of the cold air to the front by design. Try reversing it and see what happens.

 

[unostang]

Thanks for the recommendation. I tried a few different things and it seems that the rear ac is fully functional between all its temperature ranges as long as the drivers ac is set above low. If the drivers ac is on full hot, the rear ac/heat seems to work just fine.

 

[Alvenir]

You can also try synching the front and rear in settings. In that mode, whatever temperature you set up front should be the same in the rear.

 

[unostang]

Sync does seem to equalize the temps. But don’t want to have to do that every time. Do you think changing the drivers blend door would fix the issue?

 

[ibis1]

Has anyone verified that the system has the correct charge? If the system is low, the evaporators (Front & rear) will not have uniform temperature control across the coil.

 

[unostang]

Any idea on the location of the low side port on the 2019? Looked and can’t seem to find it. I searched around the web and only one video shows it next to the oil filter but it’s not there on my model year.

 

[ibis1]

May be different, but on my 2020 it is located just above and to the left of my oil fill cap.

 

[unostang]

Here are the only 2 ports I can find. They both seem to come off of the same line. Did they change the port size for the 2019 and up? Different Freon maybe? My connector will not fit on either port

 

[unostang]

Problem solved. I didn’t realize they model uses R-1234 and not the older 134. **** that new stuff is high. It was boarder line low and after filling it seems to be blowing colder

 

[ibis1]

That is the same setup my 2020 has, glad the issue is fixed. Just a reminder, anytime you are diagnosing a problem, start with the basic's before you dive deeply into the issue. I've seen ECU's replaced when the fault was a blown fuse or a faulty relay. Before I retired, we were paying $600. wholesale for a 10 pound cylinder of 1234 refrigerant.

 

[unostang]

your right about that. Should have started with the pressure. Not the cheapest but easiest for sure.

 

[huzee1]

“Check the simple things first” BEST ADVICE EVER!
Don’t ask about my $1500 PCM module replacement by dealer & discovered a week later original problem was a loose battery cable bolt.

 

[ibis1]

“Check the simple things first” BEST ADVICE EVER!
Don’t ask about my $1500 PCM module replacement by dealer & discovered a week later original problem was a loose battery cable bolt.

Have seen it many times over the years. A lot of people do not understand why auto parts stores and dealers do not take returns on electrical parts. It's for that reason, if the part does not fix the vehicle, they want to return it. There is no way to test many electrical parts, so you have to diagnose it by process of elimination, which means verifying the basics first.