Check the signal relays and fuses under the hood.
Because of the battery is not sufficient to light up the signal light.
You might try to see if your bright (brake or turn) part of your tail light is burnt out. This is probably the case if when you turn your turn signal on in one direction, it flashes alot faster than normal.
Burned out bulb Faulty socket and/or wiring/ ground Faulty turn signal flasher Faulty turn signal Switch
One of the bulbs are broken, check all of your turn signals.
You could be hitting the flash feature on the turn signal arm when you use it.
A fast flashing turn signal, on most any vehicle, is an indicator that a turn signal bulb is going out or has gone out on that side(i.e. front turn signal on passenger side flashing fast, check the rear turn signal bulb on passenger side.) This will cause the light on your dash board to flash fast as well. This is generaly a good time to replace all of the bulbs, turn signal, running lights, and break lights, as they are so cheap. Also check deck light or top break light if applicable for burn outs.
In order to fix a Mitsubishi mirage signal light that doesn't turn off, you would need to understand the wiring system. This is a problem with the wiring and the circuit that connects the power from the battery to the signal light.
The turn signal and brake light use the same bulb. When you get a fast flash, it is from a reduced electrical load being placed on the flasher unit due to a burned bulb. Replace the bulb and this should fix your problem.
If the turn signal bulbs light but will not flash, the flasher relay is defective, replace it.
Turn signal indicators are lights. The flash to tell you, or indicate, that a turn signal is on, and which way the lights are flashing.
flasher will not flash when circuit is open or shorted replace left front turn signal bulb
either a bulb or the signal flasher relay located on the fuse panel usually opposite the hazard flasher relay
If a signal light stays on, but does not flash on a 1989 Pontiac, there could be a light burned out in the turn signals on the exterior of the vehicle. It is also possible that the flasher unit has gone bad. The flasher unit is under the dash on the driver's side.