There are likely one of two reasons why a brake light on a Brava is not working. Either the bulb is burned out or a fuse is blown.
Check the brake light bulbs, Check the brake light fuse, Check the brake light switch, In that order.
the brake light driver side not working
the high level brake light strip is an array of light emitting diodes. if one or more have stopped working then you will need to get a soldering iron to them and remove them from the PCB. its far less aggro to buy a replacement from an on-line breaker as a replacement LED installed the wrong way around won't produce light.
The brake light switch is not air actuated.
probably the brake light switch on the pedal if none are working at all
possibly have a brake light out
Bulbs blown, or corroded sockets.
There are a few reasons that the third brake light is the only one working. One reason could be that there is a short in the wires of your main brake light. Another reason is that the light bulb has blown out.
The "BRAKE BULB" light means that a brake bulb is not working and may require replacing.
If your brake light is not coming on, you might have blown a fuse. You might also have a bulb that is no longer working.
The brake lights in your 1983 Nissan pickup truck are controlled by the brake light relay switch. When the brake light relay switch malfunctions the brake lights will stop working.
The brake light may be blown (bulb) or your brake light switch might not be working.