A lamp must be used on the tongue of any trailer where the distance between the front of the trailer body and the rear of the body of the towing vehicle is fifteen feet or greater, and where the top of the tongue is less than twenty-four inches above the ground at any point between the front of the body of the trailer and the rear of the body of the towing vehicle. This lamp must:

(1) Be amber in color and be in operation whenever the combination of vehicles is in motion, and must be visible to each side of the combination.

(2) Have a minimum diameter of two and one-half inches.

(3) Have a steady burn or may be flashing provided that the flashing lamp only flashes by means of an electronic or electric flasher. Strobe lamps and rotating type lamps are not permitted.

(4) Be mounted as nearly as practicable in the center of the distance between the vehicle bodies. Lamps mounted on extendable tongues will necessarily vary in distance between the bodies in relation to the amount of extension used; however, in no case will the lamp be over five feet from the center of the distance between vehicle bodies nor more than fifteen feet from either of the vehicle bodies.

(5) Be mounted at a minimum height of twenty-one inches above the roadway, and maximum height of forty-eight inches above the roadway.