I have confirmed that the later 2006 E53 diesel (Australian delivery) do not use any of the 4 larger red fuses. The fusebox has some additional fuses on the top of the fusebox that can only be accessed by removing the glove box and unbolting the fusebox unit so it can be lowered down.

The fuse used is a "MIDI" format originally designed by Littel.

Picture of the underside of the fusebox. The red/cyan wire on the right is the one that goes to the Aux fan.


The upper side of the fusebox has these fuses. The one for the AUX fan is missing as I was getting a replacement.



Picture of the new fuse in place



AUX fan now works again. I hit a kangaroo which mushed the front up pretty bad. The fuse must have blown when the AUX fan wiring was mushed up in the mess.