The tail/stop/turn light assy has to be removed from the vehicle. This is held in by either two screws on the inside edge, or nuts on the inside of the trunk under the lining. After the assy is removed, the light socket can be twisted to remove it and to replace the bulb.
Check the fuse. Then check the wiring.
If you are referring to the brake light then the brake light switch is stuck.
how to change third or center brake light on Chevy beretta 95
The brake light switch is broken or out of adjustment.
needs new alternator
The brake lights on a 96 Jimmy are operated by the brake light switch, mounted on the brake pedal assembly. If the switch is bad the lights could stay on or off, or be sporadic.
Location? Usually at the upper end of the brake pedal (under dash)
when this light is on it means that there is something wrong with your anti-lock-brake system and you should go get it checked.
Is the brake fluid level low in your brake master cylinder in the engine compartment ?
There is a compartment box between the driver seat and the passenger seat. At the bottom of the box you can find the adjusting nut.
brake light switch above the brake pedal
under the dash in the fuse box