This shows the simple insides of the emergency flasher switch. The underside of the "lid" is on the left, the mechanical part of the switch is in the half on the right. When assembled, the bumps (contacts) are inside the box across from the metal bar. The sliding bar in the box moves when the switch's lever is moved, touching the bar to the copper contacts in the base. One of those bumps on the lid was dirty, and that was the switch's only problem. It was cleaned with 600-grit sandpaper and now works like new.