Usually if the signal is blinking fast, it means there is a problem with the circuit. Usually this is caused by a lightbulb going out. They've engineered the cars to blink fast to let you know that the bulb might be out, since you usually can't see your own turn signals. I'd try replacing the rear taillight bulb first to see if that fixes the problem.
Defective flasher relay.
If the right blinker is blinking really fast, it means that there is a turn signal bulb on the right side that is burned out. (coulod be either front or rear)
It has been my experience that a rapid turn signal indicates there is a burnt-out signal light bulb (either front or rear) on the side of the rapid blinking signal. If the right signal is blinking rapidly, the problem is in the signal lights for the right side (front or rear) of the vehicle. Turn the rapid signal on and step out of the vehicle to find which bulb is not lighting.
Turn on that fast blinking signal light and check to see if the front and rear signal lights are both working, chances are you have a burned out bulb. If both front and rear bulbs are flashing fast, replace the flasher relay.
I would look at the REAR signal light on the same side of the car. It is probably not blinking at all and the bulb needs to be replaced.
The turn signal Flasher Relay is locatedâ€¦ Front seating area, center, under dash, mounted in front driver side of console.
A fast turn signal blinking can be caused by a bulb that is getting ready to out or a bad ground. Remove the bulbs and look for corrosion around the base and in the bulb socket.
A bulb has burnt out that is why it is blinking fast. Check the front and rear bulbs.
You have a broken spring in the steering column
Usually, a fast blinking turn signal means one of the outside turn signals (front, back and side) lights is burned out.
The new bulb is already burned out, not seated properly in its socket, or you replaced the wrong one. Get out and look at the signal lights while they are blinking fast. Either the front or rear light is not blinking at all. That is the one that needs to be replaced.
It means that a light bulb is out on the side where the light solid (not blinking) it could be in the front or rear of the vehicle.