Rear climate only blowing cold air

[JestersHK]

Having a weird issue with the rear climate control in our 21 YukonXL. Started noticing when remote starting the vehicle when cold out that the rear would be blowing cold air.

If i started normally it would be fine and blow warm air.

Now the past few days it's been in the teens here and the rear heat is not working at all it just blows cold air whether remote starting or not.

Craziest thing about all this is our 2022 Acadia is doing the same darn thing. No hot air on rear climate control. Acadia is still under warranty, but we just went over mileage 65k on our yukon... how convenient.

Any thing I can check? Hopefully something i can get to easily for repairs. No CEL but going to have my buddy check for codes with his scanner.

 

[Joseph Garcia]

@swathdiver may be able to provide you with some troubleshooting tips. A quality bi-directional scanner is a very valuable diagnostic tool, and it would have great value in troubleshooting your issue.

 

[swathdiver]

Yep, need a scan tool to pull BCM codes.