Normal brightness of amber markers in headlight assembly?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by pasadena_commut, Apr 22, 2026 at 1:38 AM.

  1. pasadena_commut

    pasadena_commut Senior Member

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    While waiting to pick up a passenger at night, parked on the side of the road where it was very dark, I happened to turn the headlight switch one click towards "on". This lights up the front amber lamps at the top of the unit on each side. Except I couldn't see any evidence of that on the sidewalk or street. On returning home pulled into the driveway behind another car, tried one click again, and this time the amber lights could be seen to light up, but the reflection was very dim. I had my son look at them and he said they also looked very dim when viewed directly. Like "why would they ever make it that dim"? The normal and high beams were the expected brightness when that switch was at two clicks. The outer plastic is clear, no significant cloudiness.

    I don't think I ever looked at this bulb at night before, so not sure if these were always dim (perhaps not the right bulbs installed?), if the bulbs are getting old, or some other problem, like burnt sockets. The car was in READY for these tests, with the inside voltmeter reading 14.1V, so not a low voltage issue, at least systemically.

    Or maybe these amber corner markers are always dim and there is no problem at all?

    Edit: looking out the front window, if the "door lock" button on the fob is pressed the amber lights are much brighter when they flash. From this distance I cannot tell if it is the same light coming on though.
     
  2. dolj

    dolj Senior Member

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    I don't know if I can be all that helpful, as our headlight lenses are completely clear. Our side lights (as they are called here) are white. The indicators are orange, and that is done by way of an orange lamp. There are two different bulbs for each. The details are in the owner's manual:
    upload_2026-4-22_21-13-14.png
     
  3. ChapmanF

    ChapmanF Senior Member

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    Conventional incandescent light bulbs are always (well, when they're on) slowly 'boiling' metal off of the filament, and the metal vapor wafts around inside the bulb and some ends up on the inside of the glass.

    When you look at one of these small bulbs with many many hours of operation on it, the glass can look really dark gray or, like, silvery black from the metal deposited on the inside. That'll make it a lot dimmer than it was when it was new.

    [​IMG]
     

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  4. Tombukt2

    Tombukt2 Senior Member

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    The flash to Park lights are your turn signals much brighter the lil 194 markers even my led aren't that bright.
     
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  5. BiomedO1

    BiomedO1 Senior Member

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    There is NO high-low on marker lamps, just the bulb's luminescent rating. I suppose you can have a bad ground, dimming the incandescent bulb's light output. That effectively acts like a resistor in the circuit. If you only live a few blocks from the ocean, that may be the issue. The salt air rusting your ground point.
    You can check your bulbs and wiring, if you like - but I'm assuming it's a non-problem. IMHO: You should replace the 194's with it's LED equivalent, while your there, since they're cheap ($4 for 30x). That would be a planned preventive measure.
    30x T10/194/168 White LED License Plate Interior Light Bulbs Super Bright 6500K | eBay

    Good Luck....
     
  6. pasadena_commut

    pasadena_commut Senior Member

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    This morning confirmed that the "lock door" button amber light is a different and much larger bulb than the marker light. Oddly the bigger bulb itself is amber colored while the smaller one appears to be clear behind amber plastic. The little bulb as viewed through the amber headlight plastic does not appear to be dark like the one in ChapmanF's picture.

    Regarding those LED replacements, are they visible from the side of the car when lit? The stock bulb is essentially omnidirectional, but surface mounted LED bulbs are usually pretty directional, with most of the light going along the normal vector to the chip and little emitted in the plane of the chip. For LEDs below the plane of the chip is typically completely blocked by the circuit board, whereas an incandescent can emit a fair amount of light "backwards", unless it is blocked by some part of the headlight. (The hot part is way up in the glass part of the bulb.)
     
  7. ChapmanF

    ChapmanF Senior Member

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    Some of the LED retrofit bulbs have a bunch of LED chips pointing different ways. Some might work out well.

    So far, I haven't gone down that rabbit hole with my 2010 ... the incandescents work well enough for these little incidental lights, so far I've only had to replace maybe three in the car's 16 years, and I actually have a bunch of spares accumulated over a lifetime of driving other cars that used them.
     
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