Anti thrift system light staying on

Here is a guide that will help disable the alarm if that is the issue. However, is there a story behind this? Did it just happen one day that the light stayed on? The reason I ask is on these trucks, they normally don't have this issue except when the BCM is the issue.

https://www.2carpros.com/articles/how-to-reset-a-security-system

I attached a quick diagram steps that indicate this. The unfortunate thing is we need a scan tool to confirm this. However, if none of the things suggested in the guide under the GM section work, I would bet the BCM is the issue.