When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I think that stuffs purpose was as an RF shield since it's got 100 volt DC in there. It can put out waves that can interfere with electronics.
Agreed. It sounds to me like the drain wire for the foil shield in the wiring harness. It is probably grounded at the IDM. You should be safe to cut it off or just tape it up good and leave it.
Well, it was a long and convoluted tale, but I'm glad you got it figured out. I believe I would drive my happy @ss back over to that Ford dealership and talk to the Service Manager about that, I don't see any reason for you not to be refunded whatever you spent there on their "expertise". And if they don't want to cut you a deal, let them know you will file a complaint with both Ford and with ASE.
If anyone else has this problem in the future, you can pop the contacts out of the plug and just swap locations, you don't have to cut and solder the wires. It's been a while but I think I used a paper clip to release the contacts from the plastic plug housing.