I think WAGON MAN's suggestion was best. The speaker probably does a number of chimes, so disconnecting that might make some other things not work as they should. Its funny though, all the little add-ons that are put into the later model cars that drive people insane and make them spend their time finding out how to bypass.
Yeah the only reason it pisses me off is because im a real estate agent and each property that you open on a weekend you have to put out 5 real estate open signs from your boot and then put them back again for each property all spaced like 20-50m apart, do that 5 times in a day and that blasted chime gives you the ****s!