Your rt side brake light is burned out.
The tail lights are on a separate wiring than the blinker/brake lights. Look for a blown fuse or a broken/loose wire.
The brake lights.
Probably a faulty brake light switch or the brake light switch is installed incorrectly.
whats the color circuit for the blinkers an break lights?
its the blinker control arm.if you move it back and forth you should see the two other brake lights go on as the brake is pressed.
wrong bulbs or bad earth
Check the switch
First check the fuse, or you may have a burnt out bulb
How about a malfunctioning brake light switch
check the brakelight switch. it is located under the dash where the brake pedal rests. Hey its ritchie. If you can click your blinker down and then they work its you blinker switch,but this is my monte.
the blinker switch shorted out the brake lights... really really common problem, need to replace the switch
The next thing to check is the switch that activates the brake lights. It is probably on the master cylinder.