Brake Controller Installation on 2016 BMW X5

Updated 08/20/2026 | Published 08/17/2026

Products Featured in This Question

Curt Echo Wireless Brake Controller - 7-Way Plug-in w/ Bluetooth App - Up to 2 Axles - Proportional

(1913)

$289.95

10 Gauge Wire - Blue Primary - Per Foot

(109)

$1.69

Redarc Tow-Pro Liberty Brake Controller w/ Universal Wiring Harness - Dash Knob - Proportional

(3185)

$217.00

Roadmaster Universal Stop Light Switch Kit

(702)

$128.00

Stealth Hitches Hidden Trailer Hitch Receiver w/ Towing Kit - Custom Fit - 2"

(17)

$967.00

Question:

I installed the Stealth SH85VR with the passive harness on my 2016 BMW X5 several years ago. It has worked well for my bike rack/accessories, but I am now trying to install a brake controller for towing purposes. What wiring do I need to splice into from the original passive harness install? Im particularly unsure for the brake light trigger input for the brake controller. On the X5 there is no unique wire for brake lights, only combined with left/right turn signals. I am considering the Prodigy P2 or something similar. Thanks for any help.

asked by: Travis K

Expert Reply:

Hey Travis, welcome back! It looks like you went ahead and decided on the Curt Echo Wireless Brake Controller # C51180. This won't require any splicing for installation. Simply plug it into the 7-way at the rear on your X5 and connect via the app and you're ready to go.

If you had installed a traditional brake controller like the # RED52VR you would have connected it to the blue wire from your # SH85VR. If the installer didn't connect the blue brake output wire you would have to run a new wire up to the cab using # 10-1-1. You probably would have needed the stop light switch kit # RM-751000 for the brake light switch as well.

Since the Curt Echo installs at the rear the brake output wire and switch kit are not necessary so you don't have to worry about any of that.

What will you be towing?

expert reply by: Robin H

SH85VR 7-Way
(click to enlarge)

David

8/19/2026

The Curt Echo Controller works great electrically but not so hot mechanically. Electrically, it takes current from the TVs aux output (red) and uses its internal decelerometer to produce a proper brake control signal that it sends to the trailer’s blue wire which activates the brakes proportionately. By proportionately, that means the harder you try to decelerate by pushing the TVs pedal the more braking you will get from the trailer brakes. This can all be set up with a Bluetooth app on your smart phone. The mechanical problem is that all of this weight hanging off of the TVs 7 pin connector is supported by a measly plastic pin that the Curt tries to engage. And if you lift up the connector mechanism to see the red/green/blue lights that indicate it is working correctly, if you don’t reconnect that plastic pin it is likely to fall off underway. Even with the pin connected properly it is likely to fall off due to the heavy weight of the Curt hanging down against the pin. All it takes is one mishap and you are out about $300. I supported my Curt by wrapping it and the socket with duct tape as a kludge fix. I don’t see anyway to really fix it without Curt doing a redesign and that won’t be easy. David

Robin H.

8/20/2026

@David thanks for sharing your experience with the Echo. You're right that it's important to make sure the Echo is fully seated and securely latched into the 7-way before towing. Your concern is one of the biggest complaints we see with this brake controller, and it would definitely be an expensive mistake. Curt also has the Echo In-Line Wireless Brake Controller # C79DR, which still gives you the wireless brake controller but without the concern that it will fall off. However, it mounts behind the 7-way and stays installed on the vehicle so it is a little more permanent. The real catch is that the vehicle needs a 7-way that uses a standard USCAR connector for the # C79DR to plug in.