Brake light switch - light

Discussion in 'Electrical Systems' started by Rugratman, Apr 17, 2019 at 10:11 AM.

  1. Rugratman

    Rugratman New Member

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    The parking brake light is staying on all the time.
    I can push down on the switch and it does nothing. Stay's on.

    Bad switch, or are these grounded somehow?
     
  2. Gary S

    Gary S Administrator Lifetime Gold Member

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    The brake pedal switch grounds to turn on the light, but there is also a centering switch for the master cylinder on that same line. Either one can turn on the "brake" light. Unplug the wires to them one at a time to determine which one is turning on your light.
     
  3. Rugratman

    Rugratman New Member

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    You were correct.
    When the pedal switch is grounded, and the master was plugged in. The light came on.
    I just popped the wire on the master. Thanks.
     
  4. Gary S

    Gary S Administrator Lifetime Gold Member

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    If the switch in the master cylinder is turning the light on, it indicates a pressure problem between the front and rear brakes. You could have a fluid loss or defective master cylinder so you have only two wheel brakes and not all 4.
     
  5. Rugratman

    Rugratman New Member

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    Will check that tonight. There is fluid, new in there. I will spin them, and check.
    Thanks again Gary.
     
  6. Jeep43

    Jeep43 Veteran Member

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    That shuttle valve that trips the light in the Combination valve moves under line pressure when there is no/little pressure in the other circuit......
     

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