Problems signal lights blinks fast

Generally means that a bulb is out.
When a bulb blows, then the blinker has less electrical resistance, so the blinker works at a faster pace.
Have someone in the car as you inspect all lights.
.... and! As long as you have an assistant, check the headlights, stop lights, license plate light, brake lights, emergency flashers ....

Both sides? one side?? USUALLY , if one side is blinking fast, one of the bulbs is out. turn the hazard lights on and you should be able to determine which one.

YOU HAVE AN OVERCHARGING ALTENATOR