B20.40-0009-11
Electromagnetic fan coupling
1 Fan assembly / flange and rotor
2 Shaft
3 Lock plate (2x)
4 Bolt (2x)
5 Winged ring
In the case of mechanical or electrical components failure, the electromagnetic fan coupling can be blocked mechanically.
To do so, displace (arrow) the fan / flange and rotor assembly (1) until the orifices of the lock plates (3), offset 180° and fastened to the flange, coincide with the threaded holes of the winged ring (5). Remove the bolts (4) fastened to the shaft (2) and lock the fan assembly (1). The fan assembly (1) now spins permanently at the same speed of the engine driven pulley.
With the electromagnetic fan coupling mechanically locked, it is only permitted to drive the vehicle to the closest Mercedes-Benz dealer or authorized workshop.
Only in the case of electric wiring harness faults (damaged electric wire, short-circuit etc.) one can continue with the normal operation of the electromagnetic fan coupling, after the clearing of the fault and unlocking the fan.
The bolts (4) are to be replaced after a single utilization.