A defective turn signal relay (flasher system) on a car can often be remedied by replacing a simple auto part. The challenge is in knowing which part to replace. The five tips below will help you determine which part you should check and possibly replace, if one of your car's turn signals fails to work properly. If none of the tips below identify the faulty part, you may need to have your system repaired at your auto repair shop.
1. Signal Light Comes on But Doesn't Flash
Replace the flasher.
2. None of Your Four Signal Lights Illuminate or Flash
Check your signal light fuse. Replace it if necessary.
Check your electrical circuits for a short or poor ground.
3. Signal Lights on One Side Don't Work
Check bulbs in each signal light that doesn't work. Replace those with broken elements. Check both housings for bad grounds.
4. Turn Signal on One Side Fails to Come on or Flash
Check and replace the bad bulb. Also check the light socket for corrosion that could be causing poor contact.
5. Indicator Light on Dashboard Fails to Flash
Check to see if signal light flashes. Check and replace the bad flasher.