One of the bulbs is burnt out.
If you turn on your 1999 mustang v6 car and the right signal light stays on and doesn't blink and you switch the car off and then the left signal light stays on without blinking, then you need to see a mechanic.
You have a burned out bulb on the right side. Even a the side marker bulb will affect the turn signal
Most likely, one of the right side turn signal bulbs is burned out.
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.
AnswerPossible a bad turn signal flasherYou more than likely have a blown bulb. if the flasher was bad the left side indicator on the dash would not blink. do a quick inspection around the car with the left side on and then the right, you will notice which bulb is blown.Hope this helps."85MGM"
Sounds like you simply have A burned out bulb, Turn the signal on and look at all the lights to see if any are burned out. Could be A marker light if its in the turn signal circuit.
If you mean it stays on and does not blink then check the other turn signal bulbs on the right side front/back. If it blinks but does not turn off when you make a turn then the problem is in the steering column canceler.
Typically if the turn signal lamp on the dashboard stays on (i.e. does not blink), it means you have a burned out turn signal bulb on either the front or rear of the car. This is especially true if it happens only on one side (i.e. left or right turn signal). If the problem exists on both sides of the vehicle, check your flasher unit.
If you mean that the arrow inside the dash turns on and stays on then your problem is one of the left side turn signal bulbs. Test by turning on your four way (hazard) lights and observing all lights. The one that does not flash is the bulb that needs replacing.
That usually indicates that one or more of the bulbs have burned out. Turn on the left signal, get out of the vehicle and see which bulb is NOT turning on. Replace that bulb and the signal should work again. Also the flasher may not be working for one side.
The first thing I would do is replace the flasher. The flasher is what controls the on / off of your blinkers, giving you the blink blink. If that doesn't work, it sounds like your turn signal switch is going bad. GOOD LUCK
The Blinker relay is shot, You can get a replacement one for like $3 at your local autozone.