Keep in mind that in Europe the preeminent brake setup on trailers is surge brakes so no electric brake controller provision is needed. We need to run the wires because we all like the electric brakes on our race car trailers here. For this reason I have two friends who chose to purchase Trailex race trailers with surge brakes because their dealers told them that BMW offers zero support for installing electric brakes. One dealer even stated that "modifying" the electrical system by trying to tap a trigger wire for the electric brakes would void the warranty.

I think the biggest problem is the inconsistency from dealer to dealer. I'm lucky the shop foreman at my dealer tows with an E53.

Need help guys...installing the prodigy brake controller and cant seem to figure out where the blue wire that runs from the prodigy to rear connects to?

I have the blance of the wires connected already...

- red to LCM
- white to ground
- black to hot
- blue to rear trailer connector (but where?????)

Quick update folks...

Want to thank TowX for his support through all this. His insight was very instrumental.

The entire process is now complete and tested :) Let the towing fun begin.


The hitch install took me about 7-8 hours - more than what most have noted here, but I had to take off the exhaust section completely to access the two torx botls that hold the rear bumper cover. This could have been due to the Dinan exhaust and the larger 4.8 rear bumper cover.

While the rear was all open (during the hitch install), I ended up running my power (black) and brake trigger (blue) wire for the Prodigy brake controller towards the driver footwell area where the Pridigy would mounted.

My wirring diagram for prodigy is as follow - Brake controller is mounted under the steering colum, above the right leg

RED wire = LCM module (passenger footwell - X12 connecter, which the connecter on the top - PIN 10)
BLUE wire = Ran to the trunk area to BMW hitch wirring harness - connect wire using BMW pin, part # (61 13 1 376 193) and plug it in to the blue wire coming from the trailer harness
BLACK wire = Ran to the trunk area and connected it to the battery using a 30A fuse
WHITE wire = Found a ground near the steering column and tapped it there.

I am having some issues and I hope someone can help. I did the install as described and have the following symptoms.

Have 12 V power to the pin. Have left turn signal and brake light on trailer. Have running lights on entire trailer. Have no right side brake lights or right turn signal.

I have verified that this is not a problem with the trailer.

O1, 4.4, with factory tow package and a P3

Please help! :yikes:

Thanks!

P3 Installed and working finem however an odd thing occurs...
 

Everything about the P3 installation seems to have gone very well, thanks to the installation links provided here. We wired to the LCM as has been suggested and all works perfectly... there is one oddity though.

When the manual brake lever on the P3 is pressed to the side, the "3rd" brake light of my E53 lights, no other lights on car or trailer activate.

Can anyone shed any light on this?!

Thanks in advance to all.

Best, ~"Cars"

Haven't been on the forum for quite a while, since selling the X5 for my Yukon Denali now that I've got a trailer that was too big for the X5, but I do miss it. Denali is great, far more reliable than the X5 was and a much better tow platform, but not as much fun on the back roads.

Regarding your light problem with the P3, are the trailer brakes working properly when you slide the brake controller lever? If so I'm thinking you tapped into the wrong circuit on the LCM. My only other thought would be the ground between the X5 and trailer. When I had my X5 I made sure the 7 pin round connector on the trailer had a ground to the receptacle on the X5, rather than rely on the continuity between the coupler and the ball.

Yes, the trailer brakes are working correctly when I slide the manual lever. The only light that lights when the manual break lever is pressed is the 3rd brake light on the X5, no other lights on the X5, none on the trailer...

I'm not sure I completely understand how you ensured a better ground...? Isn't the center pin of the connector ground?!

Can you explain how to not rely on the ground being established via the hitch ball, what did you connect to what, where?

Thanks,
~Cars

Connections that rely on the hitch ball for ground may not be intermittent, as there can be paint and so on in the way). A quick way to test it is to run an independent ground wire (ie a new temporary 14 gauge wire or so) from the vehicle chassis to the trailer chassis (using alligator clips if you like) and see if it makes any difference. If not, then your ground connection is likely fine. But it happens often enough that it is something to eliminate before moving to the next step.

I had a rapid turn signal on an X5 with trailer such as you would see with a bulb out. A jumper wire fixed it, indicating that the factory harness was using the hitch itself for the ground path, and not altogether successfully.

this thread is a few years old now so I do not assume anyone connected the Tekonsha RF Prodigy 90250 unit back in the day, but any one have any comment on it NOW?

OK, so I bought it and installed it on the trailer and paired to the remote in the x5 and its freaking awesome. end of story!!!!! do not buy a wired set-up and install into the vehicle. this solves that delima