I lost all the following to work, headlights, brake lights, hazard lights, interior lights, power door locks, cigarette lighter, power seats, and rear defroster?

And at one point it all came back on again, I parked the car, swung open the front passenger door, I saw my interior lights flicker and go off and everything mentioned stopped working again. All fuses are good, circuits are good. I only have one fuse box in the glove compartment. Logically I assume it must be where everything connects at the same place, but I don't know where that is. I do believe the grounds are ok. And the positive cable from the battery goes right to the starter so I don't know where a fusible link would be. The car starts, I have back up lights and my right turn signal works. The left one would work but I have to change that bulb. It just stays on when I push the level down to show I'm turning left. Please, I've been dealing with this for almost a year! I took my car to a mechanic who said he couldn't find anything, that's when all my lights and things worked again for a 15-minute drive.