first chk fuse # 9 , 7.5 amps under dash driver's fuse box

if fuse is ok go to the back, get a test lite and with brake pedal applied at the brake lite socket ,chk to see if you get power at the green wire and ground at the black wire,
if you DO NOT co
uld be a bad brake failure sensor or wiring issue

if you get both power and ground it is bad bulbs .

the high mount brake lite has different power and ground source that is why it works ,,