On DBarth there was a switch on the dash that flashed your center side lights. So your amber lights in the middle of the coach on the side. The intent was to signal somebody they were far enough ahead or behind when you were passing or a thank you. That was factory.

I have a document that lists the symbols from the switches and what the do. I will take a picture and try to post when I have a chance.

Unless you have changed things somehow. The cruise control get a ground thru the brake light bulbs. When not lit they have almost "0" ohms. As soon as they light up the residence goes way up into the thousands of ohms and the cruise shuts down.