Either the bulbs are out, there is a grounding issue in the tail lights, or the headlight switch needs to be replaced. Do the side markers work? If no then it's probably the switch. If yes, then start checking for a bad ground wire on those tail lights.
Headlights? Brake lights? Tail lights? Signal lights? Courtesy lights? Dash lights? Check engine lights? Need more info please.
Man vehicles have the dash lights and tail lights wired through the same fuse. Check your fuse box for the dash or tail light fuse. Something has most likely caused it to blow.
There is no relay for the tail lights on a Chevy Celebrity.
The headlights and the tail lights may not be working on the 1981 El Camino because of a mechanical breakdown.
If your headlights work, but your tail lights don't, your bulbs could be blown. It is possible that you have a shortage in your car.
I have a 1991 Chevy surburan and it has no tail lights and no dash lights, all fuses are good
one of two things, BAD EARTH, or Relay switch.
check the fuses - there is no fuse for the headlights.
There is a faulty ground wire in one of your tail lights or front parking/clearance lights.
i found it to be the tail light harnesses go bad . a common problem with them because the bulb sockets short out.
Most likely a fuse.
The tail light bulbs are on a different circuit than the signal light/stop light bulbs. Check for a burnt fuse or a loose wire.