FYI,

I did my 94' e420 harness a few weeks ago. I think it's faster and easier to leave the harness support @ bell housing in place and thread the new harness into it. It is mounted under the dipstick tube- so to get it out- you have the allen at the transmission, 17mm nut at the bellhousing with limited space, and the 10mm bolt at the back of the cylinder head on the passenger side.
Not a hard job at all..

Michael