My brake lights won't turn off?

Brake Light "Stuck" ON

There couold be several reasons depending on the make, model, and year of manufacture of your vehicle. Since you don't mention this info, this answer will have to be of a generic, basic nature.

The brake lights are staying on because voltage from the battery is getting to the brake light wire(s). This could be caused by:

  • The switch controlling the brake lights is not properly adjusted.
  • The switch is defective.
  • Although not frequent, a wire which is normally "hot" energized the time has somehow come into contact with the wire(s) to the brake lights. This is uncommon unless the wires have somehow rubbed together, or been pinched so as to damage the insulation on both wires so the metal conductors (wires) can make direct contact. Another cause for this type of failure is having had a short or overload condition in a wire within a harness containing several wires, including a brake light circuit wire, has overheated causing the insulation to melt and thus allowing the wires to make contact.
  • Someone who didn't know what they were doing has been jacking around with the wiring harnesses and has miss-connected the wires so that an always hot wire is connected to the brake light wiring.

There could be some other reasons which I cannot think of right now. Good luck!