'94 E320 Cabriolet Electrical Mysteries
 

Here's a strange one. I recently returned my friend's '94 E320 to him after working on his top hydraulics over the summer. All was well when I gave it to him. Now it has started displaying a rather unusual set of symptoms. The power antenna has stopped operating, along with both seatbelt butlers and when the car is started, the interior light begins blinking off and on; first 3 times, a pause, then 4 times, a pause, then 5 times, a pause and repeats the whole sequence for several minutes, then stops. Turning on the radio causes the lights to repeat the entire sequence. Battery is new and has been left disconnected for 12+ hrs to try to exorcise demons from the varied computers to no avail. Any thoughts? Is it channeling the spirit of a German worker accidentally sealed up in the chassis somewhere. Simple demonic possession? All thoughts are welcome.

Thanks in advance.

The radio antenna, seat belt presenters, and some interior light functions work off one fuse (C), as well as the trunk light.

I don't know about the blinking action. Which interior light is that?