I have a 94 E320 (very similar under the hood) with the same problem.
Dealers & independent shops are quoting about $1000 - 1100 for the job,
with harness priced at about $750.
You can go to
for a detailed look at the labor required. It's a do-it-yourself article
with excellent photos.
Please let me know where you received the harness quote, because I think
that's a great price. I'd like to order my harness from them.