bavalova, apparently you have one or more shorts to ground in the wiring. Inspect for faulty insulation in the wiring and/or loose connections to the accessories on each particular circuit. Never install a higher amperage fuse in a circuit than the fuse chart specifies. That no-no may have overloaded the wiring and caused additional problems. Based on your description of the electrical problems with your 1991 300E I wouldn't suspect that the engine wiring harness is the cause. A faulty engine wiring harness would cause the engine to run erratically. You may want to consider having a MB-trained tech diagnose your electrical problems before you complicate the situation further.

__________________
Fred Hoelzle