brake light on dash stuck on

Discussion in 'General Motoring' started by njot, Oct 8, 2007.

  1. njot

    njot Guest


    I had a brake line break on my SL2 (due to rust), at which time the
    red "brake" warning light on the dash came on.

    The brake line is fixed now, the air has been bled out of the system
    and the pedal feels like it should now.

    However, the red "brake" light is still on on the dash.
    If I disconnect the connector at the master cylinder, the light goes
    off. If I reconnect it, it goes back on.

    What can I do to get this light to turn off??

    njot, Oct 8, 2007
  2. njot

    BläBlä Guest

    Uhhh....Add brake fluid?
    BläBlä, Oct 8, 2007
  3. njot

    njot Guest

    No, it's not low. I filled it up after the brakes were bled.
    njot, Oct 9, 2007
  4. njot

    Oppie Guest

    I can't speak for the SL2 but on most cars with dual braking circuits, if
    there is an imbalance in fluid flow (or pressure) between the front and rear
    brakes, the warning light will come on. Most I have seen will reset
    themselves when the pedal is pressed and released all the way up (make sure
    that the pedal is not binding and will return all the way). I saw one car
    some time ago that the front or rear circuits had to be bled only slightly
    to restore a balance. IIRC - I've also seen cars where the brake circuits
    are diagonal and not front-rear. Sometimes you have to push the pedal down
    hard for a reset.

    The fact that you removed the connector from the master cylinder and the
    light went off means that it is not the parking brake. That one light does
    have several meanings - low fluid level, front-rear imbalance and parking

    Did you bleed the entire system or just the line which you replaced? If it
    was old enough to rust out, the entire system should be flushed till it
    drains clear.
    Oppie, Oct 9, 2007
  5. njot

    njot Guest

    Yes, I bled the entire system after putting the new line on because
    the fluid looked like coffee. I'm sure the level is high enough in
    the master cylinder, and the pedal feels like it should now.

    As you said, I also thought that once the balance had been restored to
    the system, that the switch would reset itself and the light would go

    This car DOES have a diagonal braking system- I assume all Saturns
    do. As a matter of fact I think all GM front wheel cars have had
    diagonal braking systems since they first introduced the front wheel
    drive X body cars in 1980.

    As far as I know, only rear wheel drive cars have front/rear braking
    systems. They had to do this because there is a higher percentage of
    weight over the front wheels on a front wheel drive car, and if you
    only had your rear brakes to save you, you probably couldn't stop the

    I could try stomping hard on the pedal, and also making sure if it
    comes all the way back up (make sure it's not binding), and see if
    that helps it.
    njot, Oct 10, 2007
  6. njot

    Oppie Guest

    Does the car have ABS? if so, that complicates it another level.
    Sometimes you can unscrew the sensor in question. The balance switch is
    usually a rod with pistons at both ends that is exposed to the brake
    pressure in each circuit. The rod has a Vee groove in the center. Groove is
    what the brake balance switch sits against. when a pressure imbalance
    occurs, the pistons move the rod and actuate the switch. On some of these,
    the rod is spring loaded to return to center when brake is released - others
    it is free floating.

    In any event, the rod may be stuck because of the old brake fluid. If you
    can't free it up, a new part is needed.
    Oppie, Oct 10, 2007
  7. njot

    BläBlä Guest

    You were refering to the connector attatched to the sensor in the brake
    reservoir right? Thats a fluid level sensor... Either it see's fluid,
    doesnt see fluid, or is faulty.
    That lay out, diagonal split system, was determined to be the safest
    overall. If one piston was to fail you will still have one front wheel
    and one rear wheel on opposite sides stopping you. If you locked up just
    the rear wheels or one side of the car you will almost certainly loose
    control of the vehicle.
    BläBlä, Oct 12, 2007
  8. njot

    Oppie Guest

    If it's a problem with the blake fluid level sensor, it's possible that some
    crud that got the float stuck. IIRC, the float is magnetic and rides over
    magnetic sensor. Try giving the reservoir a good rap to see if it gets
    unstuck. Can't say for sure if the tank detatches from the master cylinder
    to allow cleaning.
    Oppie, Oct 12, 2007
  9. njot

    njot Guest

    I will try tapping on the master cylinder to see if crud buildup is
    holding the rod inside the M/C in the wrong position.

    I guess if that doesn't work, I could try taking the master cylinder
    off the car, disassemble it, and try to clean it out.

    I don't know what else would work.

    njot, Oct 14, 2007
  10. njot

    njot Guest

    Oh yes, and the car DOES have ABS.
    Not sure how that changes things, though.

    njot, Oct 14, 2007
  11. njot

    Oppie Guest

    Depending on the type of ABS system, you either purge as if it was an old
    school type or use a scan tool to cycle the ABS. My lw300 uses a straight
    through flow ABS and can be bleed without any fancy tools. Other types have
    a small reservioir within the ABS module (pump and solenoids) that require
    it to be cycled in order to bleed out all old fluid and air.

    Oh yes, and the car DOES have ABS.
    Not sure how that changes things, though.

    Oppie, Oct 15, 2007
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