1. Test for 12 volts on the IGN1 fuse in the underhood fuse block.
2. If no voltage, confirm the Electronic Control Module (ECM) is grounding the Brown wire in terminal 18 in the Blue connector for the POWERTRAIN relay 29 in the underhood fuse block during cranking.
3. If it is not being grounded, ground the Brown wire to confirm the relay works and the engine will start.
4. Test all of the ECM powers and grounds.
5. Confirm the power mode data matches the actual ignition switch position in Body Control Module (BCM) data.
6. Check G101 behind the left front headlight.
7. When there is suspicion that the ignition switch may be failed, confirm that Campaign 14063A has been performed on vehicles that require it. Contact a GM dealer with the VIN number to confirm coverage. The Campaign involves replacing the ignition switch, at no charge to the vehicle owner. When having Campaign 14063A performed, Campaign 14133A pertaining to the ignition key, and Campaign 14113A pertaining to the ignition lock cylinder, should be performed at the same time if they are needed. Refer to the most current revision of all Campaigns.