Blown stop lights/hazard flasher fuse

I found the problem.

There is another "always hot" circuit protected by this fuse : the trunk lamp.
Today, as I was checking the stop lamp socket, I noticed that the trunk switch made some sparks. And the fuse blown.
The little "L" shape switch is old and visibly corroded.
In fact, the fuse blown each time I opened the trunk.

I disconnected the wire, and so far, the fuse didn't blow anymore