Electrical problems

My car is the G5 model. I was troubleshooting the rear brakes and master cylinder since the brake pedal goes down to the floor and suddenly I have no power steering, wipers do not work, speedometer does not work, and A/C blows but cooling buttons do not work. Now passenger airbag needs service is displayed in dash. I have checked all fuses and all are fine. Maybe all these issues are connected and something grounded out? Anything helps, thanks.