How do you disconnect the seat belt alarm in a 1993 Honda Accord EX?

Unplug the the wiring under the seat.

It is the same chime that is used for key-in but not for the lights-on reminder. The seat belt beeper is inside the Integrated Control Unit, located on the left kick panel. According to the wiring diagram in the Helm manual, it only cares about the driver's seat belt, which *removes* a ground from the red/blue wire on A10 of the unit when the seat belt is fastened. As I make it out, the voltage for the switch comes through the seat belt reminder light so if the light burns out, the beeper drives you out of your mind. If the seat belt warning light never comes on, replacing the bulb should restore your sanity. If it is always on, removing the ground from the seat belt switch should do it. The switch is shown as being bolted to the body somewhere under the driver's seat, on the only branch that goes under the driver's seat of the harness that goes behind the front seats. The ground is the mounting tab. Alternatively, you may find a series of small holes on the Integrated Control Unit for the beeper to beep out of, and taping over that with duct tape is better than nothing. Then it will not be able to tell you your key is in the ignition, though.

are you sure it's the seat belt alarm? maybe some wd-40 sprayed on the connection underneath the seat. take it apart, spray, re-connect. open door beeps are annoying too. maybe your open door plastic switch is not being moved enough. maybe a little duct tape on it would push it more? look for a well qualified honda electrical technician and good luck... dealer?