Aftermarket radio? If so, maybe a messed up wire with the radio, the antenna or an amp, if there's one in the trunk.

It blows with the brake, though? Not a power window, or a turn signal action? You're not messing with cruise control are you?

Triple check you also have the correct type of brake bulbs. If you use an HD bulb they can partially melt your socket.

Welcome to the forum.

Tip: if you're working with a fuse, ID the fuse(s) you've worked on because sometimes there is more than one fuse for a circuit. E.g. windows have a fuse for the relay, and a separate fuse for window motors.