Diagnostic Aids
WARNING: This page is about a different car, the 2017 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.
When a short to ground condition exists, the BCM goes into safe mode. The DTC will clear in most cases without removing the negative battery cable, but in order to restore the BCM to normal operating conditions the negative battery cable must be removed. The B+ reference circuit under normal operating conditions will illuminate a test lamp. When the BCM is in safe mode, a test lamp will no longer illuminate but the DTC will clear and the backlighting will dim normally.