Except for certain 92-95 modells, MBs never have wiring problems.
Except for those years, problems are almost always the connectors or the components themselves.
The answer to electrical problems with numerous symptoms usually means similar grounding points or similar power sources. The only way to deal with this other than when its happening is to look to the wiring diagrams and identify the systems involved and their power and ground similarities.
Bosch Master, ASE Master, L1
33 years MB technician