tail lights on 93 chevy suburban. Wont work

Is it the tail lights ,or is it the brake lights ? If it's the brake lights at the brake.pedal there is a switch that completes the circuit as the pedal is depressed they occasionally wear out but most of the time the clip that holds it in place tends to break .if it's the tail lights first determine the parking light circuits are operating . I.e. are the front marker lights on ? If they are on then the headlight switch is most likely not the culprit. In my experience on trucks and suburbans etc. They usually have trailer light connectors .some are hard wired into the harness at the rear of the vehicle .some are harness TS (plug n play ) those Ts can become faulty amd cause lighting issues .if someone has cut or tapped into the tail lights it's possible that the connections came loose or were incorrectly wired . I'd say in your case that's about a 70% chance .Good luck