Ratatat sound is caused by a pinion gear connected to two flexible racks. In my case, a spring clip had lost enough tension to stay in place. First you have to get to the motor/pinion/rack. To do that, you have to pull down the headliner a bit. Remove the overhead light module by using a knife/fine screwdriver edge to pop off the plastic covers on the lights. Remove the plastic reflectors. Then you'll find part of a metal clip inside there that you need to pull on and then push through the hole so that the entire button/light assembly will pop out. Some youtube videos sort of give you some of the idea. I removed the sun visors and sun visor holders. Very annoying to remove without special tools. This guy helped out there: https://www.youtube.com/watch?v=CineCUPe... Screw drivers didn't really work for me. Instead, two paint can-openers have the right shape to apply a force on either side to unclip them. I removed the headliner trim piece surrounding the sunroof hole. This covers a long piece of metal that...