Lights!!!!!

The only thing the ground on the does is cause the light switch dome light function to work. Has nothing to do with any of the other lights working, and has nothing to do with the door operated switches.

If the park / tail / side lights don't work, it has nothing to do with the switch ground. Might be a switch problem, might be the harness connector / other wiring problem, or socket grounds and bulbs

BRAKE lights have NOTHING to do with the light switch at all. Brake light power goes from the brake light switch "output" directly to the turn signal switch and no other place

The TS switch routes the brake light power to the rear turn signal filaments.

You can get fooled. You might think the turn is working, when it really is being grounded through the tail circuit. So check the socket grounds and bulbs. Once you have done that, if you have no brake lights, check for power OUT of the brake light switch. If you have that..........then what you have wrong is a bad turn signal switch.