Diagnostic Aids
WARNING: This page is about a different car, the 2015 Buick LaCrosse. However, it is still accessible from the selected car via links, so may be relevant.
A poor connection at the B+ terminal of the 14V power module or open 300 Amp Mega-Fuse in the engine compartment, will prevent the 14V power module from operating.
Using a carbon pile tester is the preferred method to test the 14V power module. The carbon pile tester can put an increasing load on the system to reach a target current level. If a carbon pile tester is not available, the alternative method is using the scan tool 14V power module setpoint.