Hi, 94 E320 keeps running when the key is turned off. The history: 2 years ago new factory engine wiring harness, has been fine until last week. Last week while driving there was a strong smell of sulfur and gassing from the battery, disconnected battery cable while engine running and drove another 20 minutes just fine. Park the car and turned off the ignition took out the key and engine still running, I pulled the fuel pump relay to kill the engine, no lit warning lights on dash. Next relay back in, disconnected alternator wires to see if it was back feeding ignition, started engine and turn off key engine stiil running, pulled battery cable to kill engine. Last start engine and reach behind dash and unplug ignition switch, engine still running.

Where can the ignition be getting power ? I suspect the alternator is overcharging and melted something.

StillRunning