[wangjun1972]

Originally Posted by Colibri

LED's on trailer --> throwing trailer malfunction warning in vehicle?

I installed the Tekonsha universal adapter (W/ DIODE) in the wiring system workaround/unique harness I built - everything is functioning as it should - brakes work, all lights properly etc. yet I'm getting a general malfunction warning in the vehicle (exact wording escapes me rn)... Again, I've checked and all lights and brakes are working as they should. So its really just an annoyance + if something should actually malfunction, it'd be nice to know it's actually real.

Coming from the motorcycle world, I've installed LED's (where OEM ECU expects incandescent), I've needed to install resistors to get the error codes to stop. I'm suspecting that's my case. (long thread here, skimmed/searched, just saw stuff on needing diode/backfeed errors - I may have missed something tho)

Anyone experience this, with LED's on the trailer, and find a solution?

This Curt adapter is what I used for trailer LED lights which worked well. https://www.amazon.ca/dp/B00AFVOF3M/...v_ov_lig_dp_it

[Rjking2112]

Originally Posted by Tallman152

A few more pics of the wiring and mounting.

this is awesome. I’m going to do this.

[djohn]

Huge thanks to everyone who posted about how to wire this in! Like a couple of you, I have a Tekonsha P3 controller. I also went with inside the cubby. And held from the bottom: I didn't want to have to clip and unclip to close it in there.

To get the most possible space for my fingers to go in underneath (in an emergency, for the manual control), I mounted the controller as far back as it would go. That causes the connector on the back to protrude through the hole in the back of the cubby that the cable goes through, when closed. I made that hole bigger, and it's alright. However, there's a structural pillar back there that I wasn't thinking about when everything was out of the car. The result is that the cubby barely closes.

If I were to move it so the controller is mounted a little off-center to the left, even a quarter inch, it probably wouldn't do that. But I've reached the don't-fix-it-if-it-ain't-broke stage!

[Harv]

Just reading through this thread as I’ve just bought a 23 M50i that now needs brake controller wiring. In my f15 35d I had to make my harness from the back right to under the dash and had it come out under the radio. I would hook it up to my Teconsha mounted on a cup holder mount. In this G05 all I got to do is go from the plug (already found) and make my harness to come out next to the phone charger.

Pics of my f15 set up that I hope to replicate.

John

[bono]

Why to deal with wires? I have been using wireless brake controller for the last over 50k miles without any issue.

[Harv]

Because I have multiple trailers and I have trust issues with wireless stuff. �� I know they work great for other people.

John

[bono]

Sounds good. Multiple trailers are already problematic with wireless solution. Good luck.

Originally Posted by Harv

Because I have multiple trailers and I have trust issues with wireless stuff. �� I know they work great for other people.

John

[djohn]

To save money! I already had a wired controller. There were enough costs involved with moving to the new tow vehicle.

[larsony99]

Originally Posted by gofast182

Why any of you are messing with wires, harnesses, and mounting is beyond me. In the beginning of the thread we talk about the Prodigy Wireless Brake controller. No routing wires through your car, no mounting of a controller box to your interior, just plug-and-go.

Because that's tied to a single trailer, and it's wireless instead of a wired connection. And expensive, compared to typical solutions

[jad03060]

Some wireless brake controllers are just a small, in-line device, so not physically attached to a trailer.

If you aren’t at least a little knowledgeable, you could mess things up by trying to install a controller yourself, and personally, you probably want the manual control to be a bit more accessible so you can actually get to it if needed. That’s also a problem with some of the wireless solutions, but hopefully, with the stability control built into the X5 with OEM towing capability, you won’t need that.

If you only planned to pull one trailer, the AutoBrake controller looks like an interesting choice as it can be mounted anywhere in the trailer, hidden away so unlikely to be stolen or to mess up the vehicle’s electronics if you miswire something. It automatically goes into bypass mode if it detects a controller in the vehicle.

[Harv]

Originally Posted by Di3s3l_Power

I'm adding this post and photos to help others who want to go with wired trailer brake controller (g05 X5 with towing package)

Some summary from previous posts:

The pin out of the connection from BMW connector is as follows:

Brown = Ground
Blue = To trailers brakes
Red w/stripe = +12v battery
Black w/stripe = 12v brake light trigger

your brake controller connector must match the same sequence (post #54 on this thread)

I got my matching BMW pin housing and pins from ECS but you can get from other websites (pelican porsche parts). The pin housing is shared with porsche cars.

Pin housing:
Mfg Part #
99965275840
ECS Part #
ES#1512776

https://www.ecstuning.com/b-genuine-...g/99965275840/

Circular Contact 1.0mm-2.5mm:
Mfg Part #
61131376193

https://www.ecstuning.com/b-genuine-...m/61131376193/

This is a wonderful post. Thank you!

I finished up mine today. No pics at the moment (I know! Sorry) but I made my harness come out of the center console to the right of phone charger. Fished the wires to the under dash and to the plug. Here’s directions on how to take the console apart.

https://g05.bimmerpost.com/forums/at...8&d=1606083823

My P3 sits on a coffee cup mount and is within fingertip reach if my hand is on the shifter. I remove it when not in use.

Thanks again.

[rmccomiskie]

Yes. I know this is an old thread. I'm just adding this information in case someone wants to use a controller other than a Redarc.

I am installing a Curt TriFlex Next Proportional Brake Controller in my 2021 BMW G05 X5 xDrive40i. The X5 has the factory installed tow package so it has the brake controller connector under the dash on the left side. It was just hanging there. I'll be towing a nuCamp TAB@400 teardrop camper (18', 2900 lbs dry, 3500 lbs loaded, 350 lbs tongue weight).

Having read this entire thread, the proper BMW brake controller connector pinout was still unclear to me. Post #54 in this thread said:

Brown = Ground
Blue = To trailers brakes
Red w/stripe = +12v battery
Black w/stripe = 12v brake light trigger

So, how to be sure? I fired up my multimeter. With the ignition on I found 13.7V continuous on the Red/stripe wire and 0V on the black/stripe wire. When I depressed the brake pedal, the black/stripe wire went to 13.7V. That confirms the pinout given in Post #54.

I bought the Curt TriFlex Next controller ($125, Apr 2024) from etrailer.com. It uses an internal solid state accelerometer to measure tow vehicle deceleration when the brakes are applied. It then sends the appropriate voltage on the blue wire to the trailer brakes.

I had the previous version of this controller in my 2017 Audi Q7 3.0T and it worked just fine. That was plug and play using Curt's Audi specific adapter cable. Unfortunately, Curt doesn't offer an adapter cable for the BMW X5 as discussed in this thread. eTrailer suggested using the Curt Universal Brake Control Adapter PN 51515 ($9, Apr 2024) which has bare wires on one end and a Curt controller connector on the other end. It looked to me like the Porsche Pin Holder PN 9965275840 and 4 each BMW pins PN 61131376193 suggested in this thread would work perfectly. I bought the pin holder and pins from ecstuning.com (~$10 + $10 shipping, Apr 2024).

Once I had all of the parts in hand, it was a simple matter to solder the pins to the adapter wires and snap them into the pin holder...making sure they match the corresponding wires in the BMW tow connector.

It then remained to mount the controller somewhere easily accessible while driving...just in case I need to apply just the trailer brakes. I decided to put it under the dash cubby to the left of the steering column. That's where I had the controller in my Audi Q7. A bit of a reach but not in your face or in the way. The X5 has a removable panel below the dash. I attached the controller mounting bracket to the panel with the supplied screws, routed the controller cable around the side of the panel and connected it to the adapter cable behind the dash. The adapter cable is connected to the BMW tow connector.

I haven't towed with this yet. The camper just came out of Winter storage. I'll report back here after I've confirmed full function.

Cheers.