My 2004 Accent brake lights go out constantly. I replace the fuse. The lights work. But after a short time--a drive to the grocery store and back, the brake lights do not work. I check the fuse. It's blown.
you have a dead short somewhere, the hard part is finding it, l would suspect the fault lies with one of the rear lamp clusters, try removing the wiring connector on one of the back lights then press the brake pedal a few times and see if the fuse blows, then to the same on the other side and then you can check which side is giving you the problem, there is of course other things it could be but try this first
Quick inexpensive (maybe $2) would be to replace the tail/brake bulbs)...
Tech next to me spent maybe 2hr dinking looking for short (fuse drives all kinds of lamps), another tech came up and grabs the bulb, looks really close and says your bulb is shorted down inside the the bulb base... put new bulb in, no more fuse popping.