- A flasher relay is powered off of the automobile's 12-volt DC main. It is grounded (positive or negative ground) to match the rest of the car's electrical system. Its circuit is designed for a maximum current load to power the turn and emergency signals only. Any further demand or overload will trip a circuit breaker or blow a fuse or fusible link.
- The heart of the flasher is the relay. The relay is the electromechanical device that makes the operator switch-selections happen. Typically, a switch is engaged, which energizes the electromagnet in the relay. This electromagnet closes contacts that power the flasher and lighting circuit. Left, right or both sides can be selected.
- The flasher is a thermostatic switch designed to power on and off at a set rate. Typically, flashers are set for 6 or 12 volts, depending on the application. The flasher is a complete unit and not typically designed for service.