I have a recently acquired 96 SL600 with 25,000 miles and as close to perfect as one could get.. until I heard a noise coming from the trunk on the right side. Opened the side panel inside the trunk and noticed a whole lot of all kinds of electrial things of which I have no clue. The noise is a sort of "whirring" sound, clicks, whirring...it is fairly rhythmic and lasts a few seconds then stops.. and starts again. What could this be? I'm now a little leery of taking the car any distance. I didn't hear all this with the hard top on, the soft top is up now and it is more noticeable. Does anyone have an idea about this?

 

This is the vacuum system that operates the door and trunk locks. There is a pump and vacuum lines running every which way. As long as it stops whirring, I don't think you have any problems. I have an SL500 (96) and I hear it infrequently after you lock the doors with the remote.