I was curious and I did some test..............

There are only 2 micro relays inside the Front SAM.
Relay O , is for horn.
Relay R is for Circuit 87M meaning this is engine computer and/or starting related and is very important.

German car is to follow DIN standard for its relay pin wiring.

These are the Relay R and O on my car, these are new ones a few years ago, because my then existing one was under TSB , supposedly it is problematic.


Above is made by TE Connectivity . This is a 4 pin, if it is a 5 pin version, the missing 5th pin is pin 4.





There is no equivalent numbering to indicate pin 1 and 2 is equal to pin 85 and/or 86 coil, and if pin 3 is the pin 30 power source and pin 5 is the 87 output, like the bigger relay.

The best data I can get is from Hella, but it is not exacty like TE connectivity.


Second relay above, its pin 6 would be pin 4 on my TE Connectivity Relay. The pins 1,2,3 and 5 are all exactly the same position as TE.






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For Relay O , horn.
The pin 85 is indeed minus or ground.
But pin 5 is the power source aka Pin 30 in normal size relay. This is how MB wired it as such, not complying to DIN standard.
DIN standard would use pin 3 as pin 30 power source.








Thus, MB wiring is on purpose removing any numbering of 85/86/30/87 and even 1,2,3,5 , so that they can draw as easy as they like and we must do physical check on the car.


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Relay R is following DIN standard, pin 3 being pin 30 power source as in normal size relay.



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Good thing is the pin 1 is equal to pin 85 negative for coil is consistent for both relays actual physical wiring. I marked white dot for the 85-ground.





Relay O, pin 1 or pin 85 equivalent




I will check the rest of the normal size relays.
See if they follow DIN standard for pin 30 and pin 86

Shall update..........