if all your lights went out including radio and temp control. The issue is in the instrument cluster. Some of the circuits on the board burn out. you will have to pull the cluster and look at the board for spots with no solder. it is usually in the top left part of the board
RepairPal Certified shops can diagnose and repair your 1991 Mercedes-Benz 500SL. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.