"hacking" a dimmer onto aftermarket led headlights.

Discussion in 'Gen 3 Prius Accessories and Modifications' started by Sterlingarcher6969, Mar 12, 2025.

  1. Sterlingarcher6969

    Sterlingarcher6969 Junior Member

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    Recently got some Giga turbo "the sun is approaching" LEDs for my low beams because my current ones were way dimmer than when I bought them.
    I knew they would be bright, but holy cow, they weren't kidding! The thing has a heat pipe in it, and I'm pretty sure it's illegally Bright.

    Anyway, the good thing about this is that if I can dim it to maybe 75%, they will last forever. Companies often overdrive LEDs so they don't have to put as many because high-power LEDs aren't cheap.

    I have checked with the manufacturer and the controller that is included with the bulb auto dims if the bulb gets too hot.

    That means a thermistor that I can put a potentiometer in line with to override it while still allowing the thermistor to take over if it overheats.

    Okay, so my question is, how am I going to route the wiring to one of the empty accessory slots to the left of the wheel, which are normally used for fog lights and such.

    I figured I'd make a post here before I go poking around with a multimeter.

    What's the best way to route the wiring so I'm not drilling holes and such?
     
    #1 Sterlingarcher6969, Mar 12, 2025
    Last edited: Mar 12, 2025
  2. ChapmanF

    ChapmanF Senior Member

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    Maybe you could just measure the light output, compare to legal light output, and add a fixed resistance at the bulbs. Less of a chore with wiring and modding the dash.
     
    #2 ChapmanF, Mar 12, 2025
  3. Brian1954

    Brian1954 Senior Member

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    Technically, aftermarket headlights are not legal for a car that did not have LED OEM headlights installed at the factory.

    I replaced my Gen 3 dim low beam halogen bulbs with LED aftermarket bulbs. I did not buy the brightest bulbs that were available for the reason that you are now trying to correct.
     
    #3 Brian1954, Mar 12, 2025
    Last edited: Mar 12, 2025
  4. Sterlingarcher6969

    Sterlingarcher6969 Junior Member

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    It's a nice to have feature anyways. It would be nice for when driving around at night in campgrounds and places where people are sleeping
     
    #4 Sterlingarcher6969, Mar 13, 2025
  5. black_jmyntrn

    black_jmyntrn Senior Member

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    #5 black_jmyntrn, Mar 13, 2025
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  6. Sterlingarcher6969

    Sterlingarcher6969 Junior Member

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    thanks!

    I'll give this a go
     
    #6 Sterlingarcher6969, Mar 16, 2025
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  7. black_jmyntrn

    black_jmyntrn Senior Member

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    on pins and needles waiting for your update. :) did it work out for you?
     
    #7 black_jmyntrn, Mar 17, 2025
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  8. Sterlingarcher6969

    Sterlingarcher6969 Junior Member

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    I got it working! Super simple. Just put a 50k potentiometer in parallel with the thermistor.
    I'm putting it in some time this week. I'm just going to use the hole I already drilled in the driver's side foot well for the underglow.....that I don't use. (It was fun so I don't regret it)
     

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    #8 Sterlingarcher6969, Mar 19, 2025 at 12:06 AM
  9. xliderider

    xliderider Senior Member

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    #9 xliderider, Mar 19, 2025 at 3:31 AM
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  10. black_jmyntrn

    black_jmyntrn Senior Member

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    ?

    For that broken plastic... I would take a top thats broken to a plastic storage bin then using my plastic welder, cut out enough to wrap around that box fully then use a high temp head gun to melt the bin top plastic then wrap it around that box then clamp together and it will be safe.

    so. in my experience, you have to cut a hole and its not as easy as it sounds. Oh and dont let you try and push it through and it pops out... then you are in a cold climate area with your shoes off... the draft you feel will have you ensure that grommet is air tight... plus its sooo much easier with a wire snake through the fender IMO
     
    #10 black_jmyntrn, Mar 21, 2025 at 7:24 AM
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