Outside brake lights

Maybe the brakelight switch on the brake pedal?

Brake Lights "Stuck" On

Usually this is caused by:

* The brake light switch [mounting positon] is not adjusted properly.
* The brake light switch is defective.
* Or the brake pedal is not fully returning to its designed position.

Brake Light Failure to Turn Off
IF the brake light switch is definitely good [working properly] then the most likely cause for the brake lights to remain turned on is that the position of the switch [the distance of the plunger tip from the brake pedal arm] is not adjusted properly.

Most mechanical type switches are adjusted by screwing the switch [which has a threaded mounting to a hole in the mounting bracket] either toward or away from the brake pedal arm [which depresses the switch plunger to turn off the brake lights].

It is immeasurably helpful to have an assistant stand behind the vehicle to observe and report the changes [on-off, etc.] As you make adjustments of the switch position.

You should continue to make changes in the adjustment until the brake lights stay OFF when the brake pedal is not depressed, and the brake lights come on when the pedal is depressed.

Also have you replaced any bulbs just before this happened?