How do you disconnect the seat belt alarm on the Lexus rx350?

TURN OFF SEATBELT CHIME:

1) Turn the car on but do not start the engine, keep foot off brake. Cycle your trip reset button until it reads ODO. Turn ignition back off and wait a few seconds.

2) Make sure seatbelt is not fastened.

3) Turn the ignition back on, but do not start the car, keep foot off brake. As soon as you see everything light up, press and hold the trip reset button and do a long 12 second count.

4) Keep your finger on the trip reset button! Fasten your seat belt. As soon as you fasten the seat belt you should see the ODO display go from XXXX miles to "b-on". At that time take your finger off of the trip reset button and press it again. It should cycle to "b-off". Turn off ignition and you are done.

From another source:

Seat belt chime

1. Turn the ignition switch on (without starting car)

2. Press the ODO/TRIP switch until the odometer displays "ODO"

3. Turn the ignition switch off

4. Turn the ignition switch on

5. Press ODO/TRIP switch immediately (within 6 seconds after turning the power switch ON) and hold it down for 10 seconds or more.

6. Continue holding the ODO/TRIP switch and fasten the front passenger's seat belt.

7. Check that the odometer displays either "b-on" or "b-off" (it will be "b-on")

8. Press the ODO/TRIP button to change the display to "b-off".

9. Turn the ignition switch off.