What would cause the brake warning light to come on in a Taurus - Sable?

If the emergency brake is partially on due to a sticking cable, or a weak brake master cylinder starting to go out.( does the brake feel a little spongy?)Check to make sure that the E-brake is fully released and the cable is not hanging up due to corrision.I hope this helps you. Answer but the most common answer to this question is. check the fluid on master cylinder make sure the level is not low

It may mean several things: The fluid reservoir is low & is setting the switch; there is a pressure differential problem because the master cylinder is by-passing internally; the brakes are worn and/or badly out of adjustment (on the rear drums) and the difference in apply pressure is tripping the switch on the pressure differential circuit. Get your system checked immediately. Also (and this is rare not not uncommon), the parking brake engaement switch is loose in the bracket and the transfer of weight bias (nose dive while braking) is making the parking brake light switch come on. Seen it a few times in 40+ years in the business. Be safe above all- that someone's family in front of your vehicle.

A few ideas:

  • Low brake fluid
  • Excessive brake pedal travel - have to push it nearly to the floor
  • Emergency brake is not in the fully released position

2 causes come to mind:

  1. Low brake fluid - simply check and top off if needed
  2. The brake pedal was pressed and it traveled too far - almost hitting the floor. This is a key indicator of significant problems - from time to change the brakes to possibly even problems with the power booster.
Check the brake fluid level , in your brake master cylinder , in your engine compartment and see if the brake fluid level is low