if the sound is made from the same unit that does the speed warning ding-dong then
its a bit below where the drivers left knee is (RHD car).
If you put your head down there and look up behind the plastic you should be able to see it.
looks like this
Makes a ding when you apply 12v and a dong when you take the 12v away.
Unless you put power around the wrong way, then it makes magic ...



