Passenger rear turn signal stops working periodically

On my 2013 Hyundai Elantra the rear passenger side turn signal will stop working. The interior indicator will flash quickly and the front passenger side turn signal always works even when the rear is not. It will last for a day, sometimes two and then resume normal function. The bulb was changed recently so that is not the problem. It’s just strange that it stops working and then starts working and so on and it always only affects the passenger rear signal. I’ve read that on other sites that it could be worn contacts on the turn signal switch but everything i have read indicates that problem would affect the entire side of car (front and rear) and not just the rear only. Any suggestions would be appreciated!

Is there a trailer wiring harness installed on this vehicle? The cheap clips that come with those wiring kits are notorious for being unreliable and unpredictable.

Electrical issues like this one could have one of several causes. It could be that the filament of the bulb is flopping around inside the bulb, it could be loose or worn contacts on the bulb socket, but it wouldn’t be worn contacts on the switch if the front signal is working on that side. It could also be a failing flasher unit (if they still use those).

There is really no shortcut to electrical troubleshooting. Maybe a cheap circuit tester like this one would help you test the bulb socket to see if it is getting power.

Is the bulb the same one that is also the brake light? If it is, does that work?

Sometimes the socket gets dirty or corroded a bit and you get a bad connection. Try taking out the bulb and looking in the socket. Even if it looks OK to you, take a pencil and use the eraser end to rub the brass buttons in the socket and on the bulb. Did that help?

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Try cleaning the socket with a socket brush.

And if the parts store doesn’t have these, this also works.


The symptoms seem more like the electronics are thinking there’s no bulb connected at the rear, but there is one at the front. I think you are correct, at this point in the diagnosis anyway, unlikely to be the turn signal switch (multifunction switch near the steering wheel).

Do you know how to work a volt meter? (A test light would work too, but not as well.) If so, remove the rear bulb and probe where it connects to the bulb with your volt meter. Does the volt meter jump between 0 volts and 12 volts at the same rate as the front bulb is flashing? If so that confirms a problem with the bulb or its connection to the socket.

  • clean socket and bulb (I’ve successfully used a pencil eraser for this sometimes)
  • replace bulb
  • replace socket

You could also – as a test – cut out the socket, strip the appropriate wires, and use alligator clip jumpers from the harness wires directly to the bulb. If the bulb works correctly then, you know the problem is the socket connection to the bulb.

Good idea w/this problem to poke around the two fixtures at the rear of the car to find a wire that connects to chassis ground. Make sure that wire is making a good connection at both ends.

Reminder: Whenever monkeying w/the electrical system disconnect the battery ground first.