You have a blown bulb either front or rear.
One of the bulbs is burnt out.
That's usually an indication of a burned out bulb.
POSSIBLY A BADGROUND
Check your bulbs and your flasher.
Just to the right of the steering column, close to the fire wall. Remove both plastic panels beneath the steering column to be able to see it.
you need to replace the bliker can in the fuse box.
Maybe a short somewhere...did you replace the flasher unit? No - it was blinking spuradically(?) - now I have to blink it manually and it won't blink at all with lights on.
Did you try changing the bulb? It might be burned out.
You have a burned out bulb on the right side. Even a the side marker bulb will affect the turn signal
my left turn signal on my 1997 dodge conversion van works fine,the right signal lights but does not blink,,,,any ideas
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.
Most likely, one of the right side turn signal bulbs is burned out.