I could use some help. I want to wire one of my Upfitter switches to the harness that runs the trailer lights. I want to be able to flash my trailer lights using one of the switches. Looking at some material found here it appears that everything runs through the body light module.

I don't want to screw up that module, has anyone done this and can lend some advice how to accomplish this task? Maybe a Ford tech could give me some help? I would really appreciate any help.