Check fuse for parking/tailights Could be a bad headlight switch
one of two things, BAD EARTH, or Relay switch.
my headlights work but my taillights and dash light dont work whats wrong
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.
The headlights and the tail lights may not be working on the 1981 El Camino because of a mechanical breakdown.
If the brake lights and turn signals on your 1989 Jeep Comanche are not working while the headlights and tail lights function correctly, the issue could be due to a faulty combination switch, a blown fuse, or a problem with the wiring or connectors related to those specific circuits. It's also possible that the brake light switch, located near the brake pedal, is malfunctioning. Checking these components systematically should help identify the source of the problem.
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.
Most likely a fuse.
my left tail light does'nt work
Check the ground wire to the tail lights.
Fuse, wiring, bulbs
Most likely a fuse or a bad ground.