How do you troubleshoot no brake light on a 2005 cts?

To troubleshoot a no brake light issue on a 2005 Cadillac CTS, first check the brake light bulbs to ensure they are functioning; replace any burnt-out bulbs. Next, inspect the brake light fuse in the fuse box and replace it if it's blown. Additionally, examine the brake light switch, located near the brake pedal, for proper operation; it may need adjustment or replacement if faulty. Finally, check the wiring for any signs of damage or corrosion.