The brake light switch on a Toyota Corolla is mounted to a bracket at the very top and behind the brake pedal arm. It is a small button-type of switch. When the button is extended, the circuit is closed and when the button is pushed in, as when the pedal is released, the circuit is open and no current flows.
Inspect the brake pedal stopper bracket on the top of the brake pedal arm. This bracket contacts the brake light switch button to turn off the brake lights. Problems exist with this bracket in many Toyota vehicles. A rubber plug in the bracket prevents wear on the switch button. Unfortunately, the plug often falls out. When this happens, the brake light switch button is not depressed properly when the pedal is released, keeping the brake light on.
Locate the bracket by using a flashlight. If the plug is missing there are two alternatives, replace the plug or epoxy a penny over the hole. The plug is hard to find except at the dealer, however the penny trick works great.
Remove the lower dash filler panel to gain easier access to the brake light switch using a Phillips-head screwdriver. This is not always necessary--it depends on the vehicle year and the size of the person doing the work. If you can lie on your back and reach under the dash there is no need to remove the cover, however if it is an issue remove it.
Pull the electrical plug off the brake light switch. Remove the switch using a wrench to loosen the nut next to the electrical connector. Spin the nut off the switch on the button side and pull the switch out.
Push the new switch into the hole in the bracket and install the nut on the button side of the switch. Adjust the switch by rotating the nut closest to the button so that the button contacts the brake pedal arm enough to depress the button. Push the pedal a small amount and release it. The pedal arm should come to rest without being stopped by the switch. The arm should depress the button, but nothing else. Lock down the rear nut using a wrench.
Plug the electrical connector on the switch. Install the lower dash cover.