Brake light short. Wont turn off

Discussion in 'Freightliner Forum' started by irishluck09, Dec 10, 2020.

  1. Dec 10, 2020 #1
    irishluck09

    irishluck09 Light Load Member

    295
    182
    Nov 24, 2019
    0
    2014 freightliner cascadia
    DD13 10speed

    I have a brake light that has a short somewhere and cant find it. It works as its suppose too when the truck is on but when i turn the truck off it stays on. An obvious short but not sure where. Its not the light itself as ive tested it and ive checked voltage at the plug and has voltage further up the harness somewhere.

    Just trying to see if anyone has had this issue and to see where your short was so maybe i can pinpoint the issue.


    Thanks
     
    irishluck09, Dec 10, 2020
    irishluck09, Dec 10, 2020
    #1
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  3. Dec 11, 2020 #2
    xsetra

    xsetra Road Train Member

    5,198
    7,150
    Aug 21, 2011
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    Air brake switch.
    You could have air pressure in the system that is activating the switch or a short in the switch.

    Someone else posted to let all the air out of the truck system. Drain the tanks, to determine which problem it might be.

    With key on, no air, it is a short in air switch.
     
    xsetra, Dec 11, 2020
    xsetra, Dec 11, 2020
    #2
    baha Thanks this.
  4. Dec 11, 2020 #3
    RocketyMan

    RocketyMan Medium Load Member

    552
    337
    Jun 5, 2015
    0
    We can guess/check the switch like the above post mentioned, or we can actually look up wiring for your truck as it was configured/built.

    A better question to ask would be for WIRING diagrams if you suspect a short somewhere. I can also help with general locations. In order to help you with that, last 6 of vin is needed.

    Also keep in mind you need to be more accurate in what your problem is exactly. Are your service brake lights staying on like youre applying the service brakes only with KEY OFF? Sometimes a picture is worth more than words...
     
    RocketyMan, Dec 11, 2020
    RocketyMan, Dec 11, 2020
    #3
    QUALITYTRUCK Thanks this.
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