Wiring Harness and Brake Controller Set Up for a 2009 BMW X5

Updated 06/08/2022 | Published 06/07/2022

Products Featured in This Question

Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires

(3397)

$121.25

ZCI Circuit Protected Vehicle Wiring Harness w/ 4-Pole Flat Trailer Connector and Installation Kit

(521)

$192.62

Universal Mounting Panel for Redarc Tow-Pro Trailer Brake Controller Control Knob

(358)

$13.00

Mounting Panel for Redarc Tow-Pro Trailer Brake Controller Control Knob

(733)

$13.00

Tekonsha Prodigy P3 Trailer Brake Controller - 1 to 4 Axles - Proportional

(6643)

$155.79

Redarc Tow-Pro Liberty Brake Controller - Dash Knob - Up to 2 Axles - Proportional

(2504)

$190.00

Universal Wiring Harness for Redarc Tow-Pro Trailer Brake Controllers

(420)

$27.00

Question:

Hi, I have a 2009 BMW X5 35D and would like to install trailer brake lights and brake controller so that I can rent a RV for camping. Please suggest me good product that is not too expensive and that works all the time without any issues. Thanks.

asked by: Amit S

Helpful Expert Reply:

To control your trailer's brakes and lights you will need a 7-way connector on your 2009 BMW X5. To do this you will need two separate wiring harnesses. The first is the Tekonsha ZCI Circuit Protected Vehicle Wiring Harness w/ 4-Pole Flat Trailer Connector and Installation Kit # 119250KIT. This kit will work on vehicles and trailers with either LED, incandescent, or standard bulb tail lights. It will provide you with a 4-flat vehicle connector. This connector by itself will only control the trailer's lights.

The second harness you will need is the Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires item # ETBC7. The kit includes a pre-wired 7- and 4-way trailer connector that mounts easily at the rear of your vehicle with an included bracket. This kit is designed for use on a vehicle with an existing 4-way flat trailer connector and plugs directly into it. I have linked a couple installation videos below so you can see the process.

For your brake controller I recommend the Redarc Tow-Pro Liberty Brake Controller item # RED24FR. This is a proportional brake controller that activates your trailer brakes in proportion to your vehicle's braking action. This brake controller has a unique installation method where you can mount the control knob on your dash or console and hide the main unit out of sight. You will need the Universal Wiring Harness item # RED69FR to complete your installation.

We have a couple of other mounting options for the control knob that can go inside inserts in your dash. This will give you a clean factory look install. The Universal Mounting Panel for Redarc Tow-Pro Trailer Brake Controller Control Knob item # 331-TPSI-001 which measures 1-1/4 by 1 inch. There is also the option of using the Mounting Panel for Redarc Tow-Pro Trailer Brake Controller Control Knob item # 331-TPSI-002 for the more standard knock-out measuring 1-1/4 by 7/8 inch. I have attached a couple of pictures below that show the dimensions of these mounts.