Hi fellas, uh help! I have scoured the net and taken 16 different panels off and just can’t seem to gain any ground as to what is causing my lights not to work. Apparently all lights are routed through the turn signal switch, - brake lights -hazards -turn.
Then, the signals go through a bcm, body control module, which I think is mounted below the colum and has a lot of wires going into and out of the box, but I can’t figure out how to troubleshoot the signal wire going into and exiting bcm. When I hit the turn signal, the voltage drops off two wires depending on which signal I have activated.

After the bcm, I presume they head straight to the tail and turn lights since no fuse Pulling seems to cut signal to the passenger side.

drivers side brake light, turn signal, and hazards are not working for both the front and the back. They all work fine on the passenger side. Running lights work all around.

 

I'm assuming you've tried swapping bulbs and fuses? Isn't your truck still under manufacturer warranty?

You can get electrical schematics from gmupfitter.com

 

SOLVED. Left brake, left rear turn, left front turn not working. They all run through the turn signal switch then through the Body Control Module or BCM. There are three BCM fuses under the hood and one of mine was blown causing the issues including a fast instrument panel blinker. Wiring on these are a nightmare!