I have a car (Toyota RAV4 hybrid), where nearly all lights are LEDs but for some reason Toyota engineers decided to use incandescent bulbs for the rear number plate bulb and some of the indicator bulbs.

I know that at least the rear number plate bulb may require frequent replacements because it is continuously lit (at least when the luxmeter in the car decides it's dark). But what I do not know is how long these indicator bulbs last.

On one hand, indicator bulbs are lit only very rarely.

On the other hand, indicator bulbs are cycled often, and my understanding is that incandescent bulbs don't like frequent cycling.

So, how many kilometers/miles can I expect the incandescent indicator bulbs to last?

I have never had an indicator bulb fail in a car, but then again I have not driven any single car for more than about 80 000 km.

Judging from the question Rapid Turn Signal, it seems to be the case that indicator bulbs can fail.

  • Check the manufacturer specs and look for the mtbf number (mean time before failure), vibrations and cycling exacerbate the issue and there are or were , at least for 24v, supported filament bulbs available to increase the life.
    – Solar Mike
    Jul 20, 2017 at 21:06
  • Hey mike. Those LEDs never worked. What's the damage if I add a 12v resistor? Jul 20, 2017 at 21:21
  • Not sure I'd agree with your statement that incandescent bulbs don't like frequent cycling, mainly because each time the bulb goes off, it gives it a chance to rest/cool, which should extend its life ... especially over keeping them on all the time. I'm definitely no expert here, though ... just my logically befuddled brain trying to come up with something coherent. Jul 20, 2017 at 21:35
  • Depends on the quality of the bulb.
    – Moab
    Jul 25, 2017 at 0:27

1 Answer 1


The life span of an incandescent light bulb is up to 50 times smaller than the one of an LED (in reality you can expect up to 1500-2000 hours out of an incandescent light bulb, but usually these numbers are highly overrated) However, choosing an incandescent light bulb might be the consequence of the following:

  • Incandescent light bulbs tend to be really cheap and largely available even in areas where LED's are alien technology (yes, it is possible, i have seen it myself)
  • LED's tend to be very sensible and incandescent light bulbs can withstand more abuse
  • It might actually be a marketing scheme: Toyota might have some amazing deal or some sort of a contract with a company that produces incandescent light bulbs.

Please keep in mind that those are all personal opinions.

  • May be personal opinions, but they seem to be solid thoughts and worthy of a +1. Jul 21, 2017 at 0:44

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