[timmahh]

Found it dangling in the back right of the cargo area behind the panel. Initially thought it’s the battery tender connection during shipment but seems like a lot of wires for that.

[Auricom]

Could be the harness for the trailer coupling.

All of the components within that compartment are the power distribution box/B+ distributor and main wiring harness. It's configured differently if you have M Sport Prof suspension, Comfort Access, IAS, 3rd row seating, B&W audio, and executive drive pro.

https://www.newtis.info/tisv2/a/en/g...ies/1VnddVB1cD

[timmahh]

Hmph. Interesting thought, but I’d assume the rest of the connectors would be dangling around there too. Don’t see anything else, and it looks different than the plug in the center of the TI pics, those all look pretty hefty and exposed compared to what I see.

Maybe if I connect it, it’ll transform into an M Sport 😂

[Auricom]

Originally Posted by timmahh

Hmph. Interesting thought, but I'd assume the rest of the connectors would be dangling around there too. Don't see anything else, and it looks different than the plug in the center of the TI pics, those all look pretty hefty and exposed compared to what I see.

Maybe if I connect it, it'll transform into an M Sport 😂

Without knowing how your X5 is optioned, features etc it's a bit of guessing on what that harness does.

[timmahh]

Originally Posted by Auricom

Without knowing how your X5 is optioned, features etc it's a bit of guessing on what that harness does.

Yeah I'm trying to sort through data avail on the link you posted, but it's a US sDrive 40i w/ convenience & park assist (& CA). No M-Sport, B&W, HK, IAS, 3rd row, air, exec drive pro.

[Auricom]

Here's mine, same harness not connected. I'm not inquisitive enough to find out or worry about it. Ignorance is bliss

After reviewing schematics for harness and electronic components located in the right rear compartment, deducing that it's the trailer coupling harness.

xDrive40i M Sport, premium, luxury seating (ventilated & massage), heated front/rear seats with steering wheel and arm rests, Park assistance, DA Pro, 2-axle air suspension, IAS, HK, other stuffs not harness related and did not opt for Towing package.

[timmahh]

Awesome - thanks for taking the time to check! If you notice, it's located towards the rear, so maybe it's the power connector for the trailer and would only be connected when the tow package is installed.

(Edit: I see you said the same thing, sorry!)

[James_G0540i]

My best guess is its the Trailer brake controller connector.

[tenzor]

My guess is that it's trailer wiring preparation. Noticed it was included as standard feature in configuration.
Here is hitch retrofit guide from X3 which mentions same plug https://x3.xbimmers.com/forums/attac...8;d=1571844555

[sjak92]

Thats the sea destruct harness, once plugged in, car blows up on next start up

[russelldav]

The trailer brake connector is a 4-way connector under the steering wheel, not sure why there would be two? Also the photo you posted has many more pins.

[phillydilles]

Hmm am I looking in the right spot? I don't see any free harnesses...

Working with a 2019 X5 40i XDrive with the below:
ZDY Driving Assistance Professional Package
ZLS Luxury Seating Package
ZMP M Sport Package
ZP2 Premium Package 2
ZPX Executive Package
L1CR Remote Engine Start
4HA Front & Rear Heated Seats
4HB Heated Front Seats w/Armrests & Steering Wheel
5DF Active Cruise Control
688 harman/kardon Surround Sound System

[Auricom]

Originally Posted by phillydilles

Hmm am I looking in the right spot? I don't see any free harnesses...

Working with a 2019 X5 40i XDrive with the below:
ZDY Driving Assistance Professional Package
ZLS Luxury Seating Package
ZMP M Sport Package
ZP2 Premium Package 2
ZPX Executive Package
L1CR Remote Engine Start
4HA Front & Rear Heated Seats
4HB Heated Front Seats w/Armrests & Steering Wheel
5DF Active Cruise Control
688 harman/kardon Surround Sound System

Your other right

It's the right rear panel. The left rear panel in your photo is audio amp, comms.

[tenzor]

List of standard features https://www.bmwusa.com/standard-feat...ures.20XG.html under first item Performance and efficiency it has "Trailer Hitch Prewiring"

[russelldav]

Originally Posted by tenzor

List of standard features https://www.bmwusa.com/standard-feat...ures.20XG.html under first item Performance and efficiency it has "Trailer Hitch Prewiring"

See my post above I don't think this is the trailer brake wiring as that is under the steering column in the drivers foot well

[phillydilles]

Originally Posted by Auricom

Your other right

It's the right rear panel. The left rear panel in your photo is audio amp, comms.

Success! Thank you! Now I too may join the club of the unknown plug!

[JonnyCrash]

If someone with a multimeter and the towing package wanted to have some fun, they could test which connectors from the plug that fits there on the towing package goes to which pin on the electrical connectors by the hitch. That info, if diagrammed, may allow for a 3rd party harness to be created and make life easy for people adding after market hitches. There appear to be a max of 8 pins on the plug, but I’ll bet only seven of them are used and that the oem harness splits those pins for the four using the four-pin connector on the hitch from the seven pins of the seven-pin connector.

All that is assuming that the towing package doesn’t have an extra processing module as part of the harness though.