I have a 2003 c240 and the rear shade stopped working a few months ago. When I press the up/down button, I can hear a faint "click", but nothing happens. A few weeks ago, I tried it again (I do this randomly) and it went up and came down, but hasn't worked since then. The Texas heat is just around the corner and I need all the shade I can get!!! (still need to tint the windows!). Any help would be greatly appreciated