So my mom has a Toyota Avalon 1995 and it's been having problem with the seat belt chime. I would say the chime stays on all the time even after the car is locked, the chime is also on when the car is off as well. I've checked and removed any heavy items on the seats just make sure they don't trigger the chime. Any suggestions would be appreciated.
Key on engine off, check to see if there's power at the gauge fuse. If there's power at the gauge fuse disconnect the ignition switch and recheck for power at the gauge fuse. If you have power at the gauge fuse with the ignition switch disconnected, there's a short in the integration relay or a short to power between the switch and relay.
If you wanted to disable the driver seat belt chime, ground the red/yellow wire at the buckle switch. This may not pass a safety inspection though.