What Kind of Trailer Wiring Harness Carries 12V Power for 2016 BMW X3

Updated 04/26/2016 | Published 04/22/2016

Products Featured in This Question

(66)

$14.36

Question:

Hello, I recently had a hitch installed at my dealer. I have a BMW X3, they installed the retrofit tow kit for an F25 Frame 2016. But Im not seeing the 12 volt power working. Does that not come standard with hitch installation? Could you send me a list of parts I would need? Thanks.

asked by: Anthony S

Expert Reply:

The type of wiring harness installed determines whether it will carry a 12V auxiliary power signal. The trailer wiring we offer for the 2016 BMW X3 is a 4-pole flat type setup like # 119250KIT that carries only lighting signals (stop/turn/tail).

If on the other hand your dealership installed a 7-way type trailer socket, this is designed to carry all of the lighting signals carried on the 4-pole plus up to three additional circuits, usually used for reverse lights, trailer brakes and 12V power for the trailer. If you check out the photo and wiring article I linked for you can see all of the different connector formats and how they are typically wired by function.

On an RV-style 7-way socket, such as # 37185, as you look at it from the back of the car, the contact at the 7-o-clock position is usually ground (usually on a white wire) while the contact at the 1-o-clock position is usually 12V auxiliary power (usually on a black wire). If this is the type of trailer connector your dealer installed, then you may simply need to install additional fuses or relays to activate the wiring. You can test the circuit for power using a circuit tester like # PTW2993.

Please feel free to send along a photo of your trailer connector if you still have issues after checking in with the dealership.

expert reply by: Adam R