replace third brake light and now all three don't go on. Check all light bulbs and replaced them, and still nothing.
brake lights won't go on on 1993 Honda Civic
I assume you've checked the fuses and they're not the problem. You could check for power and ground at the bulb sockets. Power should be on when the brake switch is activated and ground should be constant. Check the brake light switch on the brake pedal bracket. You could check it with a voltmeter or test light and also jump the brake light connector terminals to see if the lights go on. Check that the rest of the taillights go on when they should, they are all grounded at point 'T' at the center of the rear shelf (sedan) or the tailgate (hatchback). If the license lights, etc are OK then ground is OK, and I'd suspect that you don't have power at the brake bulbs which is most likely caused by a bad brakelight switch.