I was driving my car (Toyotal Corolla 2005) when I noticed that when turning on the right indicator the frequency at which it flashes has drastically increased. I later noticed that the right rear bulb for the indicator has gone out.

Are these two events connected? I have read that some cars do this to warn you that you have a broken bulb.

Is it as simple as replacing the bulb or do I have to fiddle with the circuit?

3 Answers 3


Yes, they are related.

Replace the rear bulb and all will be fine.

In most cars, now, the access to change the bulbs is from the inside of the car i.e. the back of the lamp. Usually removing a panel and pulling out the bulb holder is the plan of attack. Some bulb holders are twist (1/8 or 1/4 of a turn) and pull, that depends on the size and manufacturer.


Yes, they are related. Changing the burnt out light will rectify the problem. When one of the lights is burnt out less current passes through the flasher unit and it flashes faster. I don't remember the precise electronic reason for it... it's been a while.

  • 2
    The basic method was to control the current charging a capacitor and its charging time controlled the flash rate.
    – Solar Mike
    Jun 14, 2019 at 8:45
  • 4
    @SolarMike In the old days, it was a bi-metalic strip that heated up due to the current drawn by the bulbs. Because less current was drawn by a single bulb, the strip didn't get as hot, so the frequency increased. I believe modern flashers emulated this feature.
    – HandyHowie
    Jun 14, 2019 at 10:28
  • @HandyHowie those bi-metallic strip ones got slower or did not flash at all iirc and many were made by the prince of darkness aka Lucas... And I changed many of them, especially when the first electronic ones became common...
    – Solar Mike
    Jun 14, 2019 at 10:32
  • 3
    @SolarMike The ones I had experience with definitely got faster. The strip didn't get as hot, so cooled down quicker and hence closed more quickly. It was a common sight to see indicators flashing quickly.
    – HandyHowie
    Jun 14, 2019 at 10:43
  • 5
    Regardless of the electro/mechanical reason it happens, I feel it's worth pointing out that the design has remained unchanged because it's the only way you're likely to find out a bulb has burnt out.
    – Logarr
    Jun 14, 2019 at 18:17

On right side the load has reduced due to one burn out bulb, which causes it beacon fast on one side of turn signal indicator. The load should be almost same on both right and left set of bulbs. This also happens in case we use different (wrong) wattage lamp(bulbs) on left side and/or right side. Use car service manual to know the exact wattage of the blown bulb. First replace the bulb and see.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .