It isn't normal for the aux fans to routinely come on. They're called "auxiliary" for a reason, because they only come on to provide additional airflow across the condenser/radiator under conditions of high thermal loads. As for the fuse designation you say is on the printed card under the fusebox lid, I would hope that would be correct, but it doesn't agree with what the FSM electrical troubleshooting guide shows for your year M103 motor. If you have access to that document, look in Supplement 14 at pages 102-104. Someone else is going to have to chime in on that discrepancy.

__________________
1988 California version 260E (W124)
Anthracite Grey/Palomino
Owned since new and still going strong and smooth
MBCA member

Past Mercedes-Benz:
1986 190E Baby Benz
1967 230 Inherited from mom when she downsized
1959 220S Introduced me to the joys of keepin' 'em goin'

There are only 10 kinds of people in the world--those who understand binary and those who don't