brake lights on and off problem

hello

i have a 98 catera and i love it and today i noticed that when i press the brake pedal sometimes my rear brake lights will be working and sometimes not what could be causing this problem?

thanks

hello

i have a 98 catera and i love it and today i noticed that when i press the brake pedal sometimes my rear brake lights will be working and sometimes not what could be causing this problem?

thanks
Sorry so late-But if you haven't figured it out yet-Brake switches are common problem-