Tail lights and brake lights

probably burnt bulbs. Look at your tail light assembly area and find out where the screws are and taking the light housing unit off and replace the tail bub. It doesn't take 12 volts to get a light to turn on so don't be fooled by misleading bulb packages. Just b c it tells you 12 v, doesn't mean it's the bulb you need ( take the old bulb with you to make sure it's the right base / size, etc. luck

If I understand you correctly, the brake lights work but the tail lights stay off. Turn on the headlights, the tail lights should come on. If they do not, use a multi meter inside any tail light socket and check for voltage. If no voltage, keep the positive lead from the multimeter connected inside the socket to the positive voltage and touch a bare metal part of the vehicle. If voltage is now present, you have a ground problem.