I honestly don't know. I tried digging around on the workshop system but didn't find anything pertinent.

We stock both the new and old style fans. There is a production date split on the two part numbers so the engine controller could have different logic or Mercedes is just being anal again.
The aftermarket fans seem to interchange. Could it be looking for something coming back from the tachometer line?

Feed that beast a 40 amp fuel supply and hit it at 90%. See if it runs for more than 30 minutes. If so, that should do the trick. We'd lose the multi speed thing until you have time to figure that out but it should cool the engines.
My fan is supposed to run at 90% with a constant supply. It cools my engine.