managed to find someone with a diag for mercs today and got a short test done .
originally found lots of codes but once cleared all but 2 never came back the codes i know have are...
b1101 signal from control sn2 when unlocking pse/cl,cf,ata short to posative or ground b1101 actuation of unlock confirmation relay (k54) or combination relay modual n10/2 short to posative or ground
gave the same part number for both
1688200426
any thoughts before i spend the night in front of google
