Mystery Connector?
 

I have a connector hanging free in the engine department near the washer fluid bottle, which is one of three connectors from the same wire loom. The other two connectors are connected to two pumps mounted on the rear of the washer fluid bottle.

An educated guess is that this is for the Winter package headlight washer nozzles, which isn't an option on my vehicle. This haunch could be verified if someone could tell me the color of the wires going to the third pump motor (possibly mounted on the left side of the washer fluid bottle (USA models) - Brown, Black/Brown (solid stripe) of your X5 that has the Headlight washer nozzle option

Can anyone out there help me?

Attachment 21408

Attachment 21409

Your hypothesis sounds right on the money.