Safety box defective??

Hello! I have an electrical problem again. I have already found schematics etc. in the forum but I can’t do anything with it. The car has the following problem: The turn signal on the left (all three lights) lights permanently, even if the car is off and the ignition key is pulled. The error was suddenly there (had no trailer or something external connected) I then tried the fuse box and determined that it goes off when I pull the 12. Then d He blinker again but radio, climate and tacho not. And when I turn left the fuel indicator flashes with and the climate automation sometimes also.. Question: Can the fuse box be broken and cause the error (presumed by my mechanic, but no Opel expert)? Or what else can that be? I would like to hear a second opinion before we renew the thing. Thank you in advance Hanseat 81