I was taking apart my 420SEL's cluster to repaint the needles and found this:
8075 Impulses per Mile. or
12,920 Impulse per kilometer
This seems to agree with my original claim that the coding plug has to do with impulses and "setting" things internally for the signal type.
Based on this listing in a VDO PDF Catalog:
I'll have to pull on the of the SD's clusters and see what it says on the back of it. Probably will have to be the gold SD as the green one is a DD.
I found this on my 300SD:
K=10,240. It doesn't say miles or Kilometers. If we assume its in miles as the 420SEL was, then you get K=16,384 impulses per kilometer.
So in theory, If i sourced with the x4 or x5 one of them should get a newer coding style unit working on my SD..
If anyone has their cluster out of their car, can you let me know if you have a K value sticker on there?