The turn signal, also known as a blinker, is a device triggered manually inside a car to indicate the direction that a driver intends to turn. It has been in place for over 70 years, serving as a legally-mandated warning mechanism. If your turn signals begin to blink at an unusually high rate, there are several possible causes.
The main reason why turn signals start blinking really fast is a bulb failure in the head lamp. When the bulb fails to work properly because it has been damaged or broken, the resistance switches adapt to the sudden change by making the light blink repeatedly in a very fast manner.
Another reason why turn signals flash fast is if the car isn't supplied with enough voltage. Most commonly, when there is a bad combination switch, voltage supply drops instantly, thereby causing the indicator to blink really fast.
In addition, turn signals may flash really fast if the ground connection is in a bad shape. The combination switch may be dirty and require cleaning. In some cases, the screws in the ground connection area are not installed tightly enough.