Strip fuse mentioned has nothing to do with the cooling aux fans.
That is Blower/Regulator circuit fuse..
So....You want to address the two different Aux Fan circuits and you are correct on their dual functions.
Here are some test to try:
High Fan circuit verification............
On the thermostat housing, there is a blu, 2 wire sensor. With key ON , unplug that sensor. Fans should come ON high speed.
If NO, then take the top of the relay compartment behind the fuse box and look at the fuse on top of the green relay. That is first suspect.
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Test 2:
Low Fan circuit verification.......
On the reciever/drier , by radiator,....sensor with the 2 wire 6" pigtail lead..
Slide the plastic covers back off the connectors at the end of the wires and jumper there with a screwdriver..that is Low fans for a/c activation...if NO, same deal , but the Blue relay fuse..if that fuse is bad , replace with a 25 instead of the stock 15..per Benz.........................
If Yes on this test, then suspect is low refrigerant. [ not tripping the sensor b/c of lack of high pressure]
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