Hawk rear floodlights

On both campers that I took the inner walls apart on, and installed flood lights on, there is a 1/4" hole through a thicker piece of U-channel high up on the back wall.  The power wire looks like it was inserted through the hole,and then duct-taped to the outside of the U-channel before the siding was installed.  I extracted the wire and then drilled a tiny pilot hole from the inside before making a bigger hole from the outside.

In short, finding the exact spot will be very hard to do, even if you have measurements.  

I'd peel off the inside panels if doing this.