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Brake light malfunction

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Wtfdustinwtf, Jul 5, 2019.

  1. Wtfdustinwtf

    Wtfdustinwtf Junior Member

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    Hey everyone I am new here. I am driving a 2010 prius one. I am the second owner. I am having some issues I can't seem to find an answer to. Any help is much appreciAted.

    If my headlights are turned off, my brake lights work fine, but dash panel turns on. If my headlights are turned on then all three brake lights turn on and remain on in absence of braking. This car has some other electrical computer type issues as well. For example, the radio displays random characters from time to time, when I hit a bump the a!arm goes off saying key in car, sometimes the stereo just doesn't work, also the air conditioning randomly does not work. The most pressing issue here is definitely the brake light problem. Thanks for taking the time to read, double thanks for help.
     
  2. bisco

    bisco cookie crumbler

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    welcome!

    any chance of rodents chewing on the main wiring harness?
     
  3. ChapmanF

    ChapmanF Senior Member

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    Definitely sounds like that kind of a story. Rodents, or flood car, or oversize fuse installed at one time. That kind of thing.
     
  4. Wtfdustinwtf

    Wtfdustinwtf Junior Member

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    I imagine its possible, I also feel that it's likely the first owner did have this car in a flood. It started happening less than a week ago. Where would I locate the main wire harness to inspect it?
     
  5. bisco

    bisco cookie crumbler

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    it's complicated. best tool onto techinfo.toyota.com and look at the service manual and wiring schematics
     
  6. Wtfdustinwtf

    Wtfdustinwtf Junior Member

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    Thank you! Do you know anything about the Toyota code reader (not the obd2) and the software one has to download? I see Walmartsells a Toyota Prius code reader which gives more in depth information but I can't seem to find out if I need the software and if it costs.
     
    bisco likes this.
  7. Wtfdustinwtf

    Wtfdustinwtf Junior Member

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    Well, I was reading the scanner description wrong apparently it comes with the software. Some how I confused myself into thinking I had to purchase it from Toyota.
     
  8. bisco

    bisco cookie crumbler

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    toyota code reader is tech stream. you can get it on amazon, and you need a compatible laptop. there are many threads here on how to set it up and use it.
     
  9. Wtfdustinwtf

    Wtfdustinwtf Junior Member

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    So a week ago It fixed itself after I knocked the brake paddle by accident. This morning on way to work it switched back to having the stuck brake lights. From what I've been able to see so far the wiring looks good. I think I'm going to see if the Prius code reader can shed any light before taking panels out to further investigate the wiring. What's strang is everytime it starts malfunctioning the traction control light comes on even though there's no OBD2 codes to be read, then that warning light will turn off when my brake lights work normal again!
     
  10. ChapmanF

    ChapmanF Senior Member

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    There are certain kinds of problems that are sort of old-skool by nature, where the car's computer isn't likely to have any especially valuable information to give you ... this sounds like a dodgy wiring or connector issue near the switch, that kind of thing. You might not get too much help from Techstream, but with a multimeter and the wiring diagram you'll get pointed in the right direction.
     
    frodoz737 likes this.
  11. corey

    corey Junior Member

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    I am having the exact same brake light issue on my 2013 Prius V eveything works normal, but when headlights are turned on, the brake lights come on too . Along with the traction control light on the dash. When the headlights are turned off, the light system works normal again ..
    I do not have any of the other problems the original poster has ... Just the issue with the lights ..
     
  12. Wtfdustinwtf

    Wtfdustinwtf Junior Member

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    I've ways had some strange computer related issues with my prius. It's hard to fully describe but my theory is my car was flooded before I got it. So my brake light issue was intermittent, the last time it worked fine then stopped working fine I opened up the panel above the brake pedal, followed the wires I could see, check the connections I could check and happened to fine tune my brake light switch as it was a bit off. This was several months ago and the problem hasn't come back up since. Honestly I can't say me checking the connections did, or did not, do anything.
     
  13. Wtfdustinwtf

    Wtfdustinwtf Junior Member

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    Just another update for the sake of information, the issue hasn't come back up since. I took the kick panel out bellow the dash felt all connections re adjusted my brake switch so I didn't do anything special nor find any issue with it and a few days later it stoped and never did it again.
     
    Mendel Leisk likes this.