Fast-blinking turn signal lights normally indicate bulb failure in the lamp or a bad combination switch. A malfunctioned ground connection for the combination switch can also cause the turn signal lights to blink faster than usual.
The bulb in the lamp can stop functioning properly when it becomes damaged or broken. The resistance switch adjusts to this alteration by forcing the signal to blink fast and continually. When the turn signal fails to get enough voltage due to reasons such as a bad combination switch, the indicator also reacts by blinking fast and repetitively. Grime and loose screws can lead the ground connection to fail or to be in poor condition, causing the turn signal lights to blink fast.