There is no option to allow you to turn off or mute the volume  of the seat belt minder alarm of any make vehicle that I'm aware of . You can view live data in airbag SRS with Maxi Sys that display the status of the buckle switches to see if they work or not . If intent on defeating the warning You could go to the junk yard and cut off the male end of seat belt buckle or buy a seat belt extender to snap into the buckle to fool it to turn off the warning