Here is a diagram of how the brake lights work on your car. If you click on the diagram, you will then be able to see the entire diagram, instead of just the left half that you see now. I made the diagram as big as possible so that it would be easier to see. Now,moving back to how the brake lights work, there are actually two different circuits. The bulb in the tail light socket is a dual filament bulb. Power comes from the headlight switch over to the brake light switch, which breaks the circuit. When you step on the brakes, that completes the circuit in the switch, and power then proceeds from there to the turn signal switch, which sends the power on back to the tail light sockets, lighting up the brighter of the two filaments in each of the tail light bulbs. When the tail lights are not on, and you have your foot on the brake pedal, both of the brighter filaments should be on, until you activate the turn signals. Then one bulb stays light and other blinks full on/all the way off. When the tail lights are on, like when driving at night, that activates the dimmer of the two filaments in each bulb. When you step on the brake pedal, again, both bulbs are full on. When you signal a turn, one bulb will be full on and the other will blink full on/ half on, because one filament is still getting power as a tail light from the headlight switch.
The most common problems with the brake lights make up a pretty short list. At the top of that list is the bulbs are burned out in the tail lights. Always check that first. Then, it would be the plug-in connector to the tail light housing, or the socket on the housing itself, has gotten all corroded and funky looking. After that would be the brake light switch ( part # C5AB-13480-C) has gone bad. Replacing this isn't a big deal at all. It's hanging on the brake pedal arm, up above the steering column. You just unplug the two-wire connector, remove that pin that goes through the peg that the switch and the master cylinder push rod are hanging onto, pop the master cylinder push rod off of the peg and the switch will fall out into your hand. Nothing to it. On an earlier car ( like mine) the brake light switch is screwed into the front of the master cylinder, but the wiring system is the same. The only difference is the actual location of the brake light switch. Sometimes, the turn signal switch is the culprit, but normally a bad turn signal switch will make your car go retarded on you in some other way. Occassionaly it will be a problem with the wiring or the head light switch, which is the source of power for the brake lights.
How to trouble shoot the brake lights should go like this. First, check the bulbs and the sockets in the tail lights. Next, unplug the connector from the brake light switch and take a paper clip, bend it in such a way that you can stick that into both slots of the wire connector. Try not to have your skin touching any bare metal on the car when you do this, as it might deliver a little bit of a shock to you. It isn't dangerous, but it also isn't very enjoyable. If the brake lights come on, replace the brake light switch. If the brake lights don't come on, check with a volt meter to see if power is reaching the connector. If no, find out why not by checking the headight switch and connector. The wire that supplies power to the brake lights is coming out of the same slot in headlight switch connector that has the big yellow wire that supplies power to the horns. If yes to power reaching the brake light switch connector, check with the volt meter to see if power is leaving the turn signal switch at the two wire connector coming out of the steering column from the turn signal switch. If yes, your problem is in the wiring along the tail light harness somewhere. If no, your problem is in the turn signal switch, or the wiring going to or from it. Problems with this system, just like any other, are diagnosed by starting at one end and systematically going through the circuit until you find the break. You can do this.