This 2007 Chevrolet Tahoe was towed in with the complaint that the engine stopped running after running over a bump in the road. I checked codes and data and found codes B1370, B1380, B1395, B1517, B1529 and P0615 stored amongst other but these all related to the no crank condition. They are generally associated with low voltage and ignition control circuits. I proceeded to check for blown fuses. While checking the fuses in the underhood fuse box I found a problem with the #34 fuse.
It is listed as the DLIS fuse and supplies power to the ignition switch on terminal #4 and the theft deterrent module on terminal #1.
I looked around the ignition switch area for a small red/white wire and found this one that had a blue wire tapped into it. I took the blue wire out of the circuit…
…and replaced the blown fuse with a new one.
The engine now cranks and runs.
The blue wire was part of a mess of added wiring for what looked like a sound system. Blue is typically the color of the turn on circuit for an amplifier or other device. I never have understood why people will spend so much time and money doing such nonsense to a vehicle without taking the time to learn how to do it correctly. Especially their daily driver.