Check the brake light switch it's self, it should be on the brake peddle arm or bracket. The switch should show open when the peddle is neutral and should show closed when the peddle is pressed. If the switch shows nothing either way then it's hooped.
Check the bulbs. If these are OK it could be the switch on the brake pedal arm.
it maybe the brake switch
Probably the wrong bulbs or the brake lights are getting stuck "on". Or maybe a combination of the two. Check that you have the right bulbs and check to make sure something isn't keeping the brake lights on. FriPilot
Check bulbs they are double filamented with smaller for brake lights Could be a problem in steering column
Check all the fuses. If not bulbs or switch that's all that it can be,
Brake pedal switch, wiring, bulbs, bad trailer harness (if there), fuses...
it could be your brake light switch,or the fuse could be blown ,or the bulbs could be blown.or it could also be the turn signal switch.
There could be a separate fuse for the lower brake lights , or maybe both lower brake light bulbs are burned out
Likely to be the brake light switch on the pedal at fault if the bulbs and fuses are good and other lights work ok.
What year is the Ford Explorer ? There could be a separate fuse for the lower brake lights
It could be the brake light switch, usually mounted on the brake pedal.
Check the fuses first then check the bulbs.