In the pic you posted...you can see the last 7 digits of the BMW part number for this harness. Try inputting those last 7 digits into the part number search box at any of the online part database sites to see if it is still available. If it is...you can order it from your local BMW dealership's parts department...or the
"BMW xx xx x xxx xxx' (where x = the actual BMW part number) into a google search box to see if other online vendors are selling that part.
{in the pic...I can see the last 7 part number digits next the
BMW acronym...except the last digit is not legible
8 383 26?}
EDIT: Can't tell if this is what you're looking for because we can't see the entire harness in your pic...but is i #4 in the diagram and link to the part database below?