That is quite a bit of current draw, I had a 89 Sl that had a pinched wire going to the trunk light, back feeding thru high mounted stop lamp thru the brake light circuit. It was tough to get to because of the trunk hinge arm. You just have to chase those circuits, once narrowed to a fuse, pull all the consumers untill it goes away. The clock, radio, alarm, are probably out but as I recall there are other items. I noticed a faint glow in a dark garage from the tail and high mounted light.