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Discussion Starter #41
Still no progress.

Both earths at each horn plug are work8ng but no 12v.
No relay I can find related to the horn, and no 'click when activated either.

Every fuse has been tested and checked ok.

Starting to think I should start to just wire in a new cable run and relay for the horns.

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Any progress over the years?

I just bought a 2011 X5. I did not think to check the horn when I test drove and now realize the horn is inop. I have come to the same conclusion as you. There should be a relay according to the diagrams, but I can't seem to find it. Every experience I have is the same as yours. I have not dug deep into diagnosing it yet though. I just know the fuse is good and the horn does not work. I have located the horns, but have not tested for 12v at the horns nor that the horns work when bench tested. I can confirm that I do not hear a relay click under the dash when I press the horn though. I just got it and drove it home from out of state yesterday.
 

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Hello! I wonder if anyone has been able to solve this. I have a similar problem with my x5 E70. Horns suddenly stopped working. Took out and tested horns with 12v battery, both work. Checked out fuses, all ok. No horn relay seen on fuse diagram. Not sure what more to do, other than mount new horns and run cables to power and to a switch. Any help is much appreciated!
 

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what car do you have?????????????????????

year and model of E70?
 

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Ard...thanks for your response. It's a 2007 X5 4.8i (N62). Let me update on what I did yesterday. I got new horns and decided to run cables - from12v and from ground, and utilize the original steering switch. In doing so, I found out that both new horns worked, as well as the car's original horns. I then narrowed down further and found that it was only the ground that needed to be supplied to the steering switch, I didn't need to bring 12V there. I will take photos and post once I figure out how to do that here.
So, I disconnected the pair of additional horns, left original horns. It works when I press original steering switch, but then I have this one cable connecting steering ground point to a ground point under the hood...and hanging by the steering wheel.
I'm now trying to understand why the actual steering ground has failed.
At this point, is it still worth changing the JBE module?
Thanks for your help!
 

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I hate it when people start hacking up cars because they cannot figure out how it works. Or how to read a diagram. Super annoying.
Glad you paused it seem....

I dont really follow what you are doing 100%.

The horn needs power and ground. From the diagram I gave you it gets the ground at location X166. Did you find this and verify it is good?

When you press the horn button, do yoiu get 12V out at the horn? If no, when you press the horn do you get 12V at pin 9 of the JBE, which is connector X11002??

If no, then we move to the other side of the diagram- and I think this may be more uselful due to you talking aboiuyt 'needing a ground'

If you look at the diagram, the horn switch actually 'coinnects' the circuit too ground to then energize the JBE relay and turn the horn on. You need to check each of the pins on that side of the circuit to see if it is 'gettting ground'

A common failure is the cloak spring mechanism in the steering wheel.. Dunnot if this is your issue. It is A72 in the diagrams. Ground runs through it, to the horn then back out to the FRM. If you can supply ground to one side and it works, then A72 has failed.

My 2 cents
 

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Ard...those are very precious 2 cents! Let me disclose that I live on an island with no resident BMW tech, most other mechanics don't have a clue and won't even try. So I haven't much option than to 'hack' and dig into it myself. I have been able to solve various issues all along with the help of precious 2 cents here and there. I will study the diagrams and try to test the voltage at the pins you referred to.
To explain my photos: cable clipped to a ground point (I used only one of the double cable), passed through the back of the door, brought to the screw at the left side of center of the steering wheel, where the horn switch contacts when pressed, to complete the circuit. My pen point indicates those 3 main points in my cable route. Thanks once again!
 

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Ard...those are very precious 2 cents! Let me disclose that I live on an island with no resident BMW tech, most other mechanics don't have a clue and won't even try. So I haven't much option than to 'hack' and dig into it myself. I have been able to solve various issues all along with the help of precious 2 cents here and there. I will study the diagrams and try to test the voltage at the pins you referred to.
To explain my photos: cable clipped to a ground point (I used only one of the double cable), passed through the back of the door, brought to the screw at the left side of center of the steering wheel, where the horn switch contacts when pressed, to complete the circuit. My pen point indicates those 3 main points in my cable route. Thanks once again!
If you look at the schematic, there is no 'ground' on the rotating inner ring of the steering wheel- because it rotates and (obviously) cannot be 'connected' to the body ground....so...

They use a 'clockspring' to let signals get from the body to the steering wheel- a ground for the horn, other signals for the steering wheel controls.

This is referenced as A72.

I am going to guess that the one wire or contact inside the A72 that provides the ground has broken.

When you effectively bypass this module (aka A72), and just ground it yourself, the horn works, right?

One thing to check before it is definitive: is the ground TO the A72 good? So the connection in the diagram from ground location X173 to pin 1 of connector X10170. If this is a good ground then you can definitively say the clockspirng is NOT conducting the ground from pin1X10170 to pin6 if X01001

Replace the A72.http://partslinkent.com/bmw-x5-e70-clock-spring-w-combination-switches-clockspring-turn-wiper-cruise/

maybe better:

https://www.partsgeek.com/catalog/2007/bmw/x5/steering/air_bag_clockspring.html
 

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I studied the diagrams, checked JBE. The horns did work when I bypassed A72. I have placed order for a new one...should get to me in about 2 weeks or so. I actually put in current A72 about 2 years ago, when I also changed the steering angle sensor. I've been 'hacking' quite a bit for some time!! I will certainly update here- and hope some other persons find the information useful. Thanks!!
 

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I studied the diagrams, checked JBE. The horns did work when I bypassed A72. I have placed order for a new one...should get to me in about 2 weeks or so. I actually put in current A72 about 2 years ago, when I also changed the steering angle sensor. I've been 'hacking' quite a bit for some time!! I will certainly update here- and hope some other persons find the information useful. Thanks!!
huh. New or used?

Odd for a second one to fail again.

Anyway, good chasing it down!

:thumbup:
 

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Update:
I finally got to replace A72 (clockspring) with a new aftermarket product I received yesterday. The horn started working!! . .and so did the steering control buttons..vol, mute, etc.
I hope someone else finds this thread useful.

Ard: your help is much appreciated. Thanks!
 

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Cool. Thanks for closing the loop.
 

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Horn relay

I see that the thread is about 3 years old but I have the same problem with my granddaughters 2009 X5 35D. I have found that the relay is on the printed circuit board called "Body Control Module BCM ECM" Google this number 106818 10. It is the black box with 3 wiring harness' connected and plugs into the fuse block. The relay is soldered on to the PCB. I have ordered a used one and will see if that fixes the horn problem. BMW board.jpg
 

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I see that the thread is about 3 years old but I have the same problem with my granddaughters 2009 X5 35D. I have found that the relay is on the printed circuit board called "Body Control Module BCM ECM" Google this number 106818 10. It is the black box with 3 wiring harness' connected and plugs into the fuse block. The relay is soldered on to the PCB. I have ordered a used one and will see if that fixes the horn problem. View attachment 902987
Naw, we were posting in this thread just two weeks ago....

As you can see, using newtis.info it is possible to carefully narrow down the failure.

Did you do that to isolate the relay on that board???? Any specifics will help with future troubleshooting!
 

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Newtis

I worked with German printing equipment schematics for 33 years so I am not unfamiliar with reading the prints but am unfamiliar with BMW acronyms such as JBE. Actually this is the first BMW I have ever worked on. Newtis was some help with troubleshooting but I really narrowed it down to the board by listening to the clicking of the relay. I should have checked for voltage out at X11002 pin 9 when the relay was pulled in but it was about 96 degrees and I didn't have my VOM with me either. I am confident the relay on the PCB is bad;we'll see. Once I saw it was on the board I didn't go any further other than searching for a replacemnt board. Thank you for your reply.
 

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Cool;. Keep us posted.
 
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