PEUGEOT 307 XT Premium 1.6 - 2011 - LOCAS LIGHTS

Hello, how are you?
Yesterday my 307 began to turn on only the lights until finally the highs were lit without being able to turn them off even with the car off, closed and with the alarm on.
Finally I had to get the fuses so that I am not running out of battery.
I was reading that this can happen if the BSI gets wet.
The car was under the water all week because I keep it in garage discovered.
Something like this happened to someone? How did they resolve?
Is it possible to disassemble and dry the BSI to solve it?