[Phantom]

First I would check the wires from the sockets as far back to the battery as you can and check from the fuse to out, also look under the dash and check from the break switch back. After that I would remove all bulbs replace the fuse and press the break check the fuse, then reinstall one light checking the socket for an obstruction and the bulb to make sure one of the contact wires is not crossing over shorting it out. From there keep adding one light at a time till it blows.

When it blows remove the last light you tried and add the next light leaving the one it blew on out and see if it happens again. If it blew on the last light (all installed) remove one or the previous lights and use it in the last socket (the one that blew it). If it blows the fuse this time you have located the one that is grounded out and you will need to check that socket and wiring from end to start.

If it only blows with all installed it is a draw problem and could be a PIA to find or could have some corrosion on/in the wires could have happened if there was a leak in the trunk at one time and it has wicked down the wire or could be on the engine/fuse box side with the same issue.