Handbook 652 Body Electrical Diagnosis Switch Positions Sometimes switch positions can be confusing. You have to think about the application to understand proper operation. • A stop light switch is shown as a normally open switch. It is only open when it is installed, and the brake pedal is not depressed. When it is not installed, it is a closed switch. • An AC pressure switch is shown with both switches closed. Both switches are only closed when the switch is installed, and the system is within normal operating pressures. 58 Technical Training