Trailer Wiring Harness Recommendation for a 2014 BMW X3
Updated 06/02/2025 | Published 03/12/2015
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Question:
Does the following work on a 2014 BMW X3 to allow me to get brake/stop lights on a trailer? Looking to install a hitch on my vehicle. Curt Upgraded Circuit Protected Tail Light w Converter Hardwire Kit - 4 Pole End Includes Tester Curt Wiring Code C59496
asked by: Tj
Expert Reply:
The Upgraded Circuit Protected Tail Light Wiring Harness, # C59496 is not a fit for your 2014 BMW X3, they instead suggest the universal Curt Powered Tail Light Converter with 4-Pole Flat Trailer Connector
Item # C59236.
The harness that I recommend is the ZCI Circuit Protected Vehicle Wiring Harness w/ 4-Pole Flat Trailer Connector and Installation Kit # 119250KIT. I spoke with my contact at Tekonsha and he confirmed that this harness will work. While we have not yet installed this harness on a 2013 BMW X3, I have attached the installation video on a couple of other BMW models to give you a general idea. The installation will be similar to your X3 model.
I strongly recommend using the included circuit tester to test the wires on your X3 before making any splices. Vehicle manufacturers have been knows to switch wire colors between different model years, so testing the wires is the best way to determine the correct wires.
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2014x3
6/1/2025
My 2014 X3 3.5xi has four wires and the Curt 59236 works flawlessly. When I installed my converter today, I used the information @Dude found from the service manual and speaks to the X3 with four wires (not 3) on the driver's side. I suspect BMW made some wiring changes along the way or there's something really special about the 2014 X3 3.5xi? As is pointed out in the Curt instructions, all should verify their own vehicle's circuit (before making any permanent connections) with a volt/ohm meter. I'm using the Curt #59236 converter. I wired it as follows, Curt wire > X3 wire: Red > Yl/Bl Yellow > Bl/Gr Brown > Yl/Bk White > chassis ground Black > +12V constant Green > Yl/Br (passenger side) Oh yea, the converter works great the first time.