Trailer Wiring Harness Recommendation for a 2011 BMW 328xi

Question:

Hello - I already have a tow bar installed on my car, which I currently use for a behind-the-car bicycle rack. However, now I have a small motorcycle trailer and would like to tow this with my car. Would you tell me what electrical harnesss I need to purchase in order to have a completed circuit. From looking on your site I believe I need these two kits, but Id like to check with you before I order anything so I get it correct the first time. Curt 56146KIT Hopkins 46255 Thanks in advance and I look forward to ordering whatever I need from you soon. 2011 BMW 328 x drive wagon

asked by: Steve

Helpful Expert Reply:

You will only need one wiring harness to complete the trailer wiring on your 2011 BMW 328xi. The wiring harness that I would recommend for you is the ZCI Circuit Protected Vehicle Wiring Harness w/ 4-Pole Flat Trailer Connector and Installation Kit # 119250KIT. This harness uses a powered converter box that draws power from your vehicles battery for the trailer lights rather than from your tail light circuits to protect your vehicles electrical systems.

I have attached the installation instructions for this wiring harness. Keep in mind, this is a universal wiring harness, so the instructions will not be vehicle specific. Based on the information I could find, your vehicle uses a combined wiring system, so when you are installing this harness, the red wire will be grounded with the white wire. The yellow wire will attach to the wire for the left turn signal and brake light, the green wire is for the right turn signal and brake light and the brown wire is for the taillights. The black wire should be ran to the positive post on the vehicle battery. You may be able to obtain a wiring diagram from a local BMW dealer to make the process easier.

If you will be completing the installation yourself, I recommend having a good circuit tester with an incandescent bulb like part # PTW2993 to test the wires before making any connections.

expert reply by: John H