I had electrical issues on my '03 E320 for a few months (power seats not working , radiator fan working full speed , no reverse lights) CEL P0600 and SRS on . Car still started and run fine . After searching online for some time , it sounded like a BCM or rear SAM issue. Both inspected for corrosion but appeared very clean.
I swapped the BCM from my perfectly running '04 E320 Estate to my '03 E320 sedan to see if it fixes any of the electrical issues. Unfortunately not only it didn't fix any but the car stalled and wouldnt start again. I put back old BCM on the '03 and the car is not starting with that either.
Both BCM look identical with slightly different part numbers
'03 E320 : A211 540 2745
'04 E320 : A211 540 6945
Cranks and cranks but no start
My OBD2 scanner communicates with the car but cant access any modules - systems on the '03 E320

I did the TCM and TPS resets with no change .
What do you suggest in this case ??
​​​​​​​ Replace the rear sam and BCM?

 

find someone with DAS to correctly diagnose your issue all else is a FUYA which is expensive

 

Plutoe is right tonsend you to specialist.

I know nothing about how BCM is networked.

Your scanner showing zero module is concerning: car vs. scanner