If one of the direction indicator lamps burns out on the machine, the resistance in the circuit increases. On older cars, a nichrome thread heating under the influence of current played an active role in the flashing control device. If the lamp on one of the sides of the car burned out, the resistance in the circuit increased, and the simplest electromechanical device provided blinking more often - approximately twice. Thus, the driver could determine that one of the lamps was faulty without leaving the car.
In modern cars, of course, there are no heating threads in the relay. Instead, an electronic corner relay is used. It can be installed separately or be part of the comfort unit. The comfort unit, or, as it is also called, the switching unit, is on many, even inexpensive, cars. He is responsible for the smooth fading of the lighting in the cabin, the operation of the power windows, central locking and other electric "chips" of the car, including direction indicators.
As a result, the designers retained the familiar, one might say, historical function of monitoring the serviceability of direction indicator lamps. But the lamps of the direction indicator repeaters (on the wing or in the rear-view mirror housing) are small and weak (no more than 5 W) and are not checked in this way.Related Materials Choosing bulbs for the side lights - examination of ZR
So, if the relay is frequent, then one of the lamps has blown out? No, not necessarily. It is possible that the owner himself was engaged in tuning his car and decided to put LED lamps in the direction indicators. A LED lamp consumes current less than six times that way. This is the system that defines it as an open circuit. And begins to part!