Regarding the Getz

Hey, any Getz drivers in the forum? Anyway, nice to be here, I was just wondering, if anybody could help me out, how do I get rid of the rattling noise at the back of my Getz?

What I mean is when I lock my car (powerlocks), the back seems to click and then a short rattling follows. I am not quite sure what it is, hoping that someone might have some insight?

Thanks! Great forum by the way.