Check the bulbs - they are double filamented larger for tailights and smaller for stop/turn Check the fuse for parking/tail and dash lights
one of two things, BAD EARTH, or Relay switch.
my headlights work but my taillights and dash light dont work whats wrong
The dash lights and the tail lights are on the same fuse. In all probability, you have a short circuit in the tail light wiring.
The headlights and the tail lights may not be working on the 1981 El Camino because of a mechanical breakdown.
If the headlights are on and brake lights work but not the tail lights, it is possible there is a short in the electrical wires. Another cause for this could be that the tail light bulbs are burned out. Most vehicles have more than one bulb inside the tail lights to control different lights at the same time.
In the back should be tail lights which always come on when the headlights or parking lights are on, and stoplights which come on whenever the brakes are pressed. The stoplights should be brighter than the tail lights, but they should be separate.
Brake lights should NOT be effected by the headlights. Brake light function is completely independent of the headlights. Assuming you are not refering to the tail lights, or marker lights, which are supposed to come when the head lights are turned on. Not having brake lights when the head lights are on is a big safety problem and should be corrected.
try turning off your headlights
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.
check the fuses - there is no fuse for the headlights.
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.