Why would brake lights on a 98 Honda civic not come on even if the bulbs and fuse are fine?

Three words buddy. "Brake light switch". It's located right behind your brake pedal. Try replacing that. check power at the brake switch like the other person said, if there is power there then check for power at the bulb socket. If there is no power at the socket you probably have a cut wire or the relay is open. If there is no power at the socket,you need to do some trouble shooting such as contunity testing for open wires or relays.....get a multimeter and put it on the ohms setting, then attach one side to the switch and the other to the brake light socket. You should get some type of reading, if you get no reading attach the lead to the othe wire on the socket. You should get some reading, if not there is an open on the wire. You might have to mock up a pair of wires from the brake switch to the brake light socket and see if the lights come on