2015 X5 F15 DIY Guide for $400 Hitch Install w/Trailer Brake Controller

[hurleyskis]

Hello all,
I've been getting a lot of useful information off of this site so I figured I would give some back.

I am in the process of completing my hitch install on my 2015 X5 35D. I installed the Curt hitch along with a Tekonsha ZCI light controller and Hopkins iNsite brake controller.

This entire install costs ~$400 and can be done in around 5 hours depending on how picky you are with wiring etc.

I chose the Tekonsha and Hopkins so that I didn't tap into any wires on the vehicle other than the battery. The Hopkins is a great unit that I've used before and I like the remote display and controller. These can be mounted to look factory if done right.

An automotive relay is used to generate the signal that would normally come from the brake pedal switch for the brake controller. Again...didn't want to tap off the wire in the car.

This is done by tapping off the LEFT and RIGHT output signals from the Tekonsha light controller. Schottky diodes are placed in series with these signals and connected to the relay to generate the Brake switch input signal to the Hopkins.

When both the LEFT and RIGHT signals are on this will generate +12V on the Brake switch input signal to the Hopkins. This will occur if braking or if the hazard lights are flashing.

Since the Hopkins controller is an inertia controller the unit should not output anything on the Brake Out line if the vehicle is not slowing. This should prevent the trailer from braking with hazards turned on.

I have attached the wiring diagram and details on all the parts required. Some parts have a direct link to Amazon...others just search using the description which is from Amazon.
I will follow up with photos of my completed install and some tips ASAP.

Good Luck!

[ZFRED10]

Great Write Up, but wouldn't it be just as cheap to use the curt hitch with the factory wire harness you can buy for $176? Or am I missing something?

[hurleyskis]

This $400 install includes the hitch, wiring for trailer, AND the brake controller.

The $176 BMW harness + $183 hitch + $200 prodigy brake controller = $559
That doesn't including any programming charges to enable the harness if you can't do it yourself.

So it's $159 less and you have a WAY nicer brake controller that doesn't look like it was made in the 70s

[9mmkungfu]

You also need an AAG module to use the factory harness.

[Sedoy]

Any updates on pictures of your installation?

Originally Posted by hurleyskis

I have attached the wiring diagram and details on all the parts required. Some parts have a direct link to Amazon...others just search using the description which is from Amazon.
I will follow up with photos of my completed install and some tips ASAP.

Good Luck!

[hurleyskis]

Here are a few pics of the install.

A couple things changed from the original wiring diagram:

• I decided the large fuse/circuit breaker feeding the fuse block wasn't needed.
  The fuse block was so close to the battery nothing is going to short out the large cable
• The controller and display actually use two different connector types so i updated the diagram to call out the proper extension cables.

I will post the updated diagram in the next few days.

The hardest part of the install is routing the cables for the remote control and display, but the end result is worth it.

Routing the cables:
The control switch cable runs under steering wheel and immediately goes towards passenger side. It easily routes in the gap above the center console ashtray area and the preset button area. From here i routed it over to the fuse block in the passenger footwell and added an extension harness.

The display was mounted just above mirror and the harness routed in the headliner and down behind the airbag pillar trim into the passenger footwell near the fuse block. This is also where i added the extension harness.

From here both harnesses were routed in the trim along the floor and passed into the rear of the vehicle on the passenger side, exiting near the rear fuse block.

As you can see in the photos i routed the harnessing for the trailer connector out through an existing hole in the floor on passenger side. All the harnesses were routed inside a protective loom to prevent and rubbing etc.

I spent quite a bit of time figuring out where to mount the components. You can see each piece in the photos. You may or may not be able to use the same locations based on your particular vehicle. The only thing to remember is the brake controller module needs to be oriented in a specific direction in order to sense the inertia properly.

A couple of observations:
The control switch has an LED that will always be on if power is applied to the brake controller. This means when the vehicle is off the LED will stay illuminated. I was a little concerned, but then i measured the total current draw when vehicle was off and it was less than 12mA. Not an issue in my opinion. If i were going to leave the vehicle for weeks at a time i would simply unplug that fuse.

I'm still dialing in the settings, but i have no braking with only the hazards flashing! Success!

I would allow a full 6 hours if doing the complete install of hitch and all electronics at the same time. I broke it up and did the hitch one day and electronics another.

Please let me know if you have any questions.

P.S. Maybe you noticed the phone mount/wireless charger....can't recommend this enough. No magnet required super clean looking install where i put it. It's from Spiegel.

[john-k]

My apologies for replying to an old thread but I really need some advice on this particular setup.
Hurleyskis, is the ZCI controller still working perfectly fine? Only difference I believe between our cars is X5 has 2 wire setup and x6 has 3 wire. The rest should be same.

Here is my short story:

First I purchased basic Curt Trailer Controller ($60) for my BMW F16 X6 and it worked perfect for 15 minutes and then ended up having my tail lights ALWAYS ON and other lights stopped working.
After some research I found your ZCI 119250/251 Module and after the installation it also worked perfectly for a few days. and then similar to the previous module, now all lights are ALWAYS ON.
Tried resetting, checked the ground connection, checked all connections. All fine.
Tail, Left Turn and Right Turn lights are ALWAYS on. Even when the ignition is off.
What could be the problem. Any idea? I'd appreciate any sort of advice at this point.
Thanks.
-John

[Mr.bennett]

Thanks’