It takes some time to understand how stuff works. Example: The door switches are wired to the CLP/SSM so it knows when to set off the alarm if a door is opened while armed.
But that information is also used to turn the interior lights on and off - so the CLP/SSM has to tell the BCM when to turn the interior lights on.

Many think the door switches are wired to the BCM, but they aren't.



The insanity comes in when you look at the liftgate switch (trunk lid switch), they wired it to BOTH modules. I cant figure THAT out, what where they thinking?