RMT668,

here is where you got stuck.

The waires that seem to descend down driver side fender, do NOT.
Open the pictured black box's lid and there you see that the engine wire harness end attaches to other wires inside this junction box.
Unscrew the retaining nut closest to the front of the car. That releases the wire harness end that you could not figure out.

Attached Thumbnails

 

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD