[jkeady]

So you have a couple of things to think about here. Do you need a full 12v+ to activate your LED brake light system? If not, you could get power off of the trailer brake signal if you have a brake controller in your rig.

The second challenge is, a lot of trailer brake controllers are wired so they come on with the hazard lights on (just because they are getting a signal from the brake light switch and that circuit goes high with the hazards on). There are devices sold called pulse eliminators (probably similar devices with other names, too, which I suspect are just big diodes) that keep power from the hazard switch from feeding back through the brake controller and that keeps your trailer brakes from being actuated while your hazards are on.

If you don’t have a brake controller OR if you need a full 12+v to activate your LEDs, you’re going to have to run a new wire from the brake light switch and isolate it from the hazard light switch as mentioned above. OR you could add a second brake light switch to the pedal and build a totally separate circuit. Clear as mud?