Here is the Mercedes ML W164, GL X164, R-class W251 installation instructions
In these models Mercedes use 2 kinds of EZS (also named EIS-electronic ignition switch): in older cars <2007 - with 9S12 processor, in new cars 2007+ - EZS with AMAZONAS processor. Mercedes CAN filter will work with both EZS types. For installation remove EZS from car.
For first prepare Mercedes CAN filter board: remove resistor marked in picture and solder first configuration points. Use fine KYNAR wire for installation.
Remove from EZS board SMD part marked with red “X”. With short, good isolated wire connect Mercedes CAN filter to EZS board according picture: 1-1 (C1H), 2-2(C1L), 3-3(C2H), 4-4(C2L), 5-5(GND), and 6-6 (+5V).
Mercedes ML W164, GL X164, R-class W251 Type 1:
Mercedes ML W164, GL X164, R-class W251 Type 2:
After connection insulate Mercedes CAN filter board with heat shrink or insulation tape. Put it carefully to EZS casing.