Most modern cars that have electronically switched lighting systems use a process of cutting power to the consumer if there is no load on that circuit. As an example, recently fixed the rear lights on a Peugeot with corroded pins to the bulb holder. Put a test light on the circuit and no power to it,as there was no load. Key off , wait a few seconds ,and power is restored with wiring fixed. Not sure where you can read up on this.