Two problems related to wiring have been reported for the 2007 Mercedes Benz E320. The most recently reported issues are listed below.
The insulation on the wiring harnesses for the headlights has completely disintegrated and is sitting in a pile of bits on the bottom of the headlight assembly, literally leaving completely bare wires leading up to the headlamp sockets. If these wires were to touch and short out it could result in complete loss of headlights at night at highway speed. This defect was discovered when attempting to replace a burned out low beam headlight bulb. Other such wiring in the vehicle might also have deteriorated or disintegrated but not yet been discovered, with attendant risks of damage to other extremely expensive parts of the electrical system, or risk of fire or catastrophic failure of the vehicle while operating at highway speeds.
My 1994 E320 wiring harness has totally dried up and cracked in numerous places. Resulting in electrical problems and money spent on trouble shooting.