Problem with abs

Discussion in 'Audio & Electronics' started by RamV10-, Dec 17, 2016.

  1. dudeman2009

    dudeman2009 Senior Member

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    Its possible, but I cannot find the spec for that in the factory service manual. What i'd do, is take it somewhere with low traction, and slam the brakes to see if the fronts lockup. If they do, its very possible that the fronts are bad.

    However, the ABS sensors are simply copper wire wrapped around an iron core. What that test is supposed to detect is whether or not the sensor has shorted or become open. I'm not so sure about the RAM sensors, but most GM sensors are considered good if they fall within 800-1800ohms. What I would do is check the sensors themselves and make sure they are clean and free of damage.

    Where you measured will also have an impact, you should measure as close to the ABS module as possible as the wire leading up to it will add to the resistance.
     
  2. RamV10-

    RamV10- Junior Member

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    I checked the front sensor in the wheels and are perfect.
    I measured the front sensors resistance in the ABS control module connector.
    the ABS and parking lights come on just release the brake pedal,
    exactly when the pins 5 and 6 are combined.
    PIN 5 Brake lamp switch output
    PIN 6 Fused B(+)
    [​IMG]
     
  3. dudeman2009

    dudeman2009 Senior Member

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    Pins 5 and 6 should make contact only when the pedal is depressed, when the plunger is allowed to extend. When the pedal is allowed to return to its resting position, and the plunger is retracted, those pins should not make contact.

    If they are making contact when the pedal is at a resting state, the switch should be replaced.

    The pedal setup is not like in other vehicles, where depressing the brake pedal depresses the brake switch. Its completely the opposite, when you depress the brake pedal, the brake switch is released.

    Those two pins, 5 and 6 make no contact with the ABS module or PCM. If what you're saying is the ABS light only comes on when the brake pedal is resting, then you have another problem, especially if cruise and the brake lights work properly.

    If you want to test this, remove the brake switch and manually actuate it in your hand, keeping in mind that depressing the plunger is like letting your foot off the brakes.
     
  4. RamV10-

    RamV10- Junior Member

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    This is my brake switch:
    Brake depressed and switch extended
    pins 1 and 2 continue
    pins 3 and 4 does not continue
    pins 5 and 6 does not continue
    Brake released and switch retracted
    pins 1 and 2 does not continue
    pins 3 and 4 continue
    pins 5 and 6 continue
    If i remove the brake switch the abs and park lights stay off
     
  5. dudeman2009

    dudeman2009 Senior Member

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    Something is wrong then. I'm not sure if the service manual is incorrect, or there is a mistake in what switch is installed in your vehicle.

    Pins 5&6 and pins 1&2 should only have continuity when the brake pedal is depressed and plunger extended.

    When the pedal is resting only pins 3&4 should have continuity.

    I'd try to get a part number and match it up with something online.

    Do your brake lights stay on constantly until you actually hit the brakes?
     
  6. RamV10-

    RamV10- Junior Member

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    Yes
     
  7. dudeman2009

    dudeman2009 Senior Member

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    If your brake lights stay on until you actually hit the brakes, i'd say you have a faulty brake switch, or the wrong part. You can get replacements at autozone for $10-15.

    I'd go get one of those and hook it up and test it by hand just to see if it works. If not, as long as you dont scratch it up, you should be able to return it if thats not it, or they gave you the wrong part.
     
  8. RamV10-

    RamV10- Junior Member

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    Today I received the package from the USA with the new brake lamp switch. I replaced it with the broken one but nothing the abs light is always on just release the pedal
     
  9. RamV10-

    RamV10- Junior Member

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    Nobody can help me?
     
  10. dudeman2009

    dudeman2009 Senior Member

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    I'll have to read through everything again, I remember your problem, but not the details.
     

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