Impressive diagnostics skills. Let us know how it works out. I would try to find junkyard harnesses if this is possible. I'll bet dealership retail prices will be in the $150-$200 range.
You can set up a business account with the dealership for discounts on parts for "The Hobbit Automotive Repair Emporium", tell them you will pay upon receipt (no charge account) and pay tax (no Federal I.D. number needed). This can be done in about 10 minutes at all dealerships and auto parts stores and generally saves about 10-15% immediately. You don't need business cards or letter head from your "company" and since your paying taxes there's no problem with the Feds. You won't get the deeper discounts that real busy shops get, but 15% is what it is. Mo money!
Then use a lot of dielectric grease to keep out....you know.