I'll be interested to find out the definitive answer, since I believe it applies to the 400E too. I have a separate 15amp fuse on a little outrigger box next to the main fuse box, but this one does NOT control the aux fans, or if it does, it is not the ONLY fuse for them. Three summers ago while in Kansas City, my aux fans refused to work. All fuses in the main box were OK. The 15 amp separate fuse had blown, but replacing it didn't fix the problem. Took the car to the local dealer (Aristocrat Motors) and the tech took off the air cleaner and a few other things on the top of the engine to get to another fuse (as near as I could tell from a distance, watching from the waiting room). Has worked fine ever since. They didn't even charge me for the fix, but I sure wish I was smart enough to ask him WHERE in heck that fuse is, since nobody I've talked with since seemed to know what I was talking about.
I am absolutely sure that in my car, at least, there is a hidden fuse SOMEWHERE on the top of the engine but distant from the fuse box.