Does anyone know the best way to wire in the 3rd brake light for a truck cap? I attempted to run off of the left rear corner lights but the brake and blinker seem to be running through the same wires....i.e. my 3rd brake light on my cap would flash when I had the left blinker on....

I have the wiring for a trailer, is the brake light wire seperated from the blinkers on that assembly? If so I could splice into that...

Any ideas?

 

There is a seperate wire for the high mount brake light. It runs directly from the brake pedal switch. If your truck has a high mount light already, you could find the wire feeding it(possibly behind the seat area), and tap into it, and run it back to the truck cap.