I'm going to do this exact thing to my light bar
Get a relay from your auto parts store. Tell em what your gonna do, they'll take care of you.
I went to my dealer and they looked up the wiring dia on the headlights. After looking at me like I was a little loony. (nothing I'm not used to)
Looks like your looking for the yellow-violet wire to break. That's your switch wire.
Hope this helps