2002 Yukon XL / AC always on

[noodlesandsam2]

So, I got this guy in April of 2023 - AC never worked right. With all this current heat, I decided to charge it. I get it charged, and it works. It works ok, but I noticed that if I press the A/C button, and the yellow light goes out, I still have cold air coming out. This is the Automatic AC of the 3 dial type. Any suggestions?

 

[OBSandaNNBS]

So, I got this guy in April of 2023 - AC never worked right. With all this current heat, I decided to charge it. I get it charged, and it works. It works ok, but I noticed that if I press the A/C button, and the yellow light goes out, I still have cold air coming out. This is the Automatic AC of the 3 dial type. Any suggestions?

Since none of the other more knowledgeable folks have responded, I seem to recall this is a common issue, and the control module is failing. But not sure. Hopefully this bump will give you more visibility too

 

[Marky Dissod]

If the ReCirc function is in effect, the AC compressor usually kicks in even when not requested by the AC button.

 

[OR VietVet]

If the ReCirc function is in effect, the AC compressor usually kicks in even when not requested by the AC button.

Yes, when a/c is on, the recirc button should be on and lit up. When a/c is off the recirc light should go out by itself but maybe should be turned off. Unsure right now because mine is working fine and am not paying attention. You could also try disconnecting both battery cables from battery and then wait about 2-3 minutes and touch cables together and then let sit for 15 minutes and then reattach the cables and see if the system resets.

I never use my auto a/c. I do not trust it. I do it all manually and set where I want and adjust as needed.

Or, get a live data/bi-directional scanner and see what is showing up when you do turn on and off.

 

[noodlesandsam2]

Recirc is off. I have not tried to see how it behaves with the button off, and Auto off. But a manual setting is only really a fan speed. - The temp is a value - if not at max, and I don't think it is a Blend door issue. I will try and let you know.

I do need a scanner that does body stuff. Any reccomendations other than the Tech II clones ( which is where I am leaning )

 

[tooleyondeck]

I had that issue on my 2000 Silvy and what it ended up being was that I overcharged the system and the evaporator would basically freeze over to where even if I turned off the compressor it would still blow cold for about 5min or so from air passing through the ice-cold evaporator. The only way for you to 100% verify that is to take your dash apart but based on your description that may be what's happening.

 

[OR VietVet]

Recirc is off. I have not tried to see how it behaves with the button off, and Auto off. But a manual setting is only really a fan speed. - The temp is a value - if not at max, and I don't think it is a Blend door issue. I will try and let you know.

I do need a scanner that does body stuff. Any reccomendations other than the Tech II clones ( which is where I am leaning )

https://www.amazon.com/FOXWELL-NT630-Plus-Bi-Directional-Calibration/dp/B07CSMJJK9/ref=sr_1_9?crid=1BPQG60LGE2GG&dib=eyJ2IjoiMSJ9.eDquQcReZZ6nXeiUb7qQLsAwL0e6LW5Q8or2oQyQUN9g5mJBTJcXeuhFNCsjaGC63UUWgt0FPN2t2_rPm0NCQ118kSYM6QD6B9woeLO3S_4MYtesBG8lK_QROiaFwl6J7-I-IOzWqvq5Ay08cJNuOK-KgQGjwF1syH2kRphjkXk_llf7PSj0Oberd8S84wz6PYkgyh_UkoagYgm7iNw_7tmmEFA3ijJuIZBeYDLEMdrnkmd3jdA8ciMfi1k1KdxqU6cNZXBhRmOjVnqIYZI0ARSUT_b6SEG8qGMvqBruJwU.NFOWCwyZHVrunb_a4DRDnqSR8tOd8ACjbGJuDiVxILg&dib_tag=se&keywords=foxwell+bi-directional+scanner&qid=1752516528&sprefix=foxwell+bi-directional+scanner%2Caps%2C141&sr=8-9