Electrical issues 97 jimmy

97 Jimmy sl. Have multiple failures and want to know if these components have a common grounding location. Items that have failed are : rear hatch release button, horn, hazard light switch, 12v plug [cigarette lighter], key on or lights on buzzer indicator and interior lights. Everything else seems to work fine. I've also noticed a little bobbing of the fuel level arm but not overly concerned with that. I've looked at some schematics but I'm not too good at reading them. Thanks for any help.