Emergency light wiring through third brake light Silverado 2500 2016

[thardy]

Anyone ever wire an emergency light through the third brake light?  I bought a bracket that fits behind the brake light and puts the emergency strobe right on the back middle of the cab.  I am trying to find how to run the wires up to the light inside the back of the cab.  Obviously, there is a harness that plugs into the light assembly.  I would like to know if there is a way I can run the wires through the back of the inside of the cab in the same place so it can come out of the existing opening. I do not wan to drill holes.  If I can get to the back side of the that lens I am good.  The light has its own small harness and I do not need to splice into any of the existing brake wiring.  I just need to how how to run the wires through the truck.  I would think the existing wires run up behind the passenger door behind the driver.  Thanks for any help.  

[two miles uphill]

You have to drop the headliner to get access to the back of the third brake light.

[lovecars]

It's much easier to go from the inside driver side fuse box. 

Go to gm upfitters. They let you download the electrical diagrams that show where you can grab power for auxiliary lamps. The third brake light circuit will not accept any other loads. Plus the harness only has power when the light goes on.

 

I'm giving you a generic answer, if you let me know what kind of light you want to hook up I can give you more options.

[LOWDOUGH]

@lovecars I have 2017 1500 WT with the Auxiliary Roof-Mounted Lamp option. There might be a part of your harness that goes to where that switch would be in the upper console/ map light area. If so, you could get power from there. You may have already solved your problem by now though.