I drive a 98 Subaru Forester and last month the village cop pulled me over for having no brake lights. It turned out to be a blown fuse for the brake lights so I replaced it, problem solved. Well, I got pulled over by the same cop, in the same place tonight. Blown fuse for the brake lights. It seems like a fuse should last more than a few weeks. Is there a problem which would over tax the fuse?
Check the bulb holders and the wiring harness connection to the light assembly for corrosion. Check the fuse holder, too, although that’s probably OK.
Chase
You seem to misunderstand the purpose of a fuse. It prevents melted wiring and maybe a fire when there’s an electrical problem like a short circuit. Replacing the fuse doesn’t fix the underlying problem.
Like previously said, fuses are for circuit protection. I would clean & check all the sockets and replace all the bulbs. Do not forget the rear window brake light. Use a little bulb grease on the sockets before installing the new bulbs. As chaissos said, look for chaffed or burnt wires.
I recently worked on a Legacy Outback that had the same trouble. The problem turned out to be due to slightly melted wires in the back side of the brake light socket for the left side. The ground lead for the socket was touching the brake light wire. The small wire assembly which had two sockets tied to it needed to be replaced. I can only speculate that the socket may have had a faulty connection to the socket ground and that caused it to heat up and melt the wires.
If you have exposed wires for a trailer harness check that also.