On a 96' accord my spoiler brake light lights up but the high mount brake light in the rear window doesn't is it supposed to?
Because you have a spoiler, Honda likely decided to not even
include a light socket for the high mount brake light (behind rear
window). It's because the spoiler fin blocks this high mount light
Pop the trunk and check to see if a light bulb socket even exists for the high mount brake assembly. If a socket doesn't exist (and you don't see one hanging) then no worries, it was a Honda decision. This is the case for my 2000 Accord EX.