This could be a control module issue but we need to start with checking for codes and finding out if there are any pointing in a different direction. We should do a CAN scan which is easy and can check the BCM, you can get a CAN scanner (Controller Area Network) from Amazon from about $32.00 here is a video to show you how.
https://youtu.be/u-4syLc-ifQ
and
https://www.2carpros.com/articles/can-scan-controller-area-network-easy
Amazon CAN scanner link:
https://amzn.to/3sX8MCX
Once we know what are there we can take the next steps but the process to test the Body ECU.
Also, I attached the process to replace the ECU below.
Please let us know if you have other questions. Thanks
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Wednesday, May 26th, 2021 AT 8:40 PM