Most possible this issue where here earlier...... sorry, but I don,t see keyword search option in the forum. After all I detected, DIAKOIM air conditioning circuits some confusion.
According the wiring diagram first stage relay 15 amp fused for pre resistor mode ,activated ECT sensor , second stage 30 A fused relay activated the A/C compr. pressure switch. In case I close pressures witch auxiliary fan must run full speed without ignation.

Because not run, I checked the relay (below the fuse box), surprise: 15 A fuse burned out, on the first stage relay. I put a new fuse in, the fans running with closed pressure switch run slow speed -

What is that? it is possible the wiring diagram not correct, something is there some connection what not show.....???

The wiring diagrams from MB are correct - the blue relay is the slow speed relay and is switched on when ground is channeled from the switch in the drier (two brown wires)

the high speed function (green relay with 30 AMP fuse) is called by the push button unit in the dashboard - the push button unit has its own "engine coolant temperature sensor". Its usually the most forwards installed 2 pin item on the engine.

When the PBU sees high coolant temperature (105C it will close the relay and the fans go full speed)

the wiring is present at the resistor itself, the two wires that join the resistor output leg are that, one is resistor ouput (blue relay circuit) and one is resistor bypass (green relay circuit)

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)