Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

Please follow the links below to help get you started!

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > X Series > X3 F25 (2011 - current)

X3 F25 (2011 - current)
The latest X3 brings some added style and some new features to the BMW SUV family. Talk about the new F25 now!

Reply
 
Thread Tools Display Modes
  #1  
Old 06-26-2013, 10:53 AM
SpaceManGray SpaceManGray is offline
Registered User
Location: Wisconsin
 
Join Date: Aug 2012
Posts: 88
Mein Auto: 2011 X3 35i
Disable backup sensor warning during towing?

So far, I've only used my tow hitch for a bicycle rack. When I put the vehicle in reverse, the backup warning comes on at full alert level because it thinks I'm about to hit the bicycle mounted to the back end.

Does anyone know if the backup warning is disabled when a proper trailer is plugged into the hitch wiring harness? If so, any idea how I could fake it / terminate the plug to disable the backup sensor when I'm towing my bike?
__________________
2011 X3 (F25) xDrive 35i 3.0L, nav, xm
Reply With Quote
Advertisement
  #2  
Old 06-26-2013, 12:27 PM
poker838 poker838 is offline
Officially Welcomed to the 'Fest
Location: Toronto
 
Join Date: Jul 2011
Posts: 207
Mein Auto: F25 x28 n52 + n20 / B8 A4
The parking sensors have a disable button on the centre console, down to the left of the shifter. Not sure if you're looking for that, or for a permanent solution?
Reply With Quote
  #3  
Old 06-26-2013, 12:48 PM
SpaceManGray SpaceManGray is offline
Registered User
Location: Wisconsin
 
Join Date: Aug 2012
Posts: 88
Mein Auto: 2011 X3 35i
Quote:
Originally Posted by poker838 View Post
The parking sensors have a disable button on the centre console, down to the left of the shifter. Not sure if you're looking for that, or for a permanent solution?
It's a good point; I should have been more clear. I still want to see the backup camera since I can see through the bike, I just don't want to hear the noise since it's useless when there's a bike there. I guess I'm wondering if anyone with a trailer can confirm that the backup warning noise is disabled when a trailer is plugged in?
__________________
2011 X3 (F25) xDrive 35i 3.0L, nav, xm
Reply With Quote
  #4  
Old 06-26-2013, 03:08 PM
roadkillrob roadkillrob is online now
Officially Welcomed to the 'Fest
Location: Boston
 
Join Date: Aug 2006
Posts: 2,447
Mein Auto: 325CIC, 335CIC
The system disables the backup sensors when it sees the load for the trailer electrical system plugged into the trailer hitch (why you put it in reverse it actually puts a little picture of a trailer hitch on the screen). I have heard of other people just using some resistors on a plug to simulate a little load on the circuit, the car is basically putting a tiny amount of voltage on the circuit and looking for a drop to determine if something is plugged in.

I don't know if this will work, but you can get a plug circuit tester with led's on it that will light up to show you if your trailer plug is working or not - you could just plug this in and if it provides a tiny bit of a load, it would tell the car to disable the backup sensors, otherwise you might have to make something yourself with resistors.

http://www.amazon.com/Trailer-Wiring.../dp/B0065R1D2Q

Let us know how you make out if you try it - I might try it myself as I have a bike rack I put on sometimes - be nice if BMW provided a plug to disable the sensors with the hitch as it is a common issue.

Rob
__________________
2008 335i Vert Montego/Saddle/Grey Poplar
2014 X3 35i Space Grey/Chestnut/Fineline Wave
Reply With Quote
  #5  
Old 06-26-2013, 09:13 PM
SpaceManGray SpaceManGray is offline
Registered User
Location: Wisconsin
 
Join Date: Aug 2012
Posts: 88
Mein Auto: 2011 X3 35i
Quote:
Originally Posted by roadkillrob View Post
I don't know if this will work, but you can get a plug circuit tester with led's on it that will light up to show you if your trailer plug is working or not - you could just plug this in and if it provides a tiny bit of a load, it would tell the car to disable the backup sensors, otherwise you might have to make something yourself with resistors.
Great idea. I just ordered one and I'll let you know how it works out. Thanks for the suggestion.
__________________
2011 X3 (F25) xDrive 35i 3.0L, nav, xm
Reply With Quote
  #6  
Old 06-27-2013, 09:51 AM
invisihitch invisihitch is offline
'Fest Sponsor
Location: Atlanta
 
Join Date: Nov 2012
Posts: 279
Mein Auto: 2012 X3
I wish I had seen this yesterday (or perhaps you can still cancel your order for the LED-based circuit tester). We use an LED tester here, and the LEDs do not provide enough resistance for the harness to sense that a trailer is plugged in.
Reply With Quote
  #7  
Old 06-27-2013, 10:01 AM
SpaceManGray SpaceManGray is offline
Registered User
Location: Wisconsin
 
Join Date: Aug 2012
Posts: 88
Mein Auto: 2011 X3 35i
Quote:
Originally Posted by invisihitch View Post
I wish I had seen this yesterday (or perhaps you can still cancel your order for the LED-based circuit tester). We use an LED tester here, and the LEDs do not provide enough resistance for the harness to sense that a trailer is plugged in.
Order has already shipped, but thanks anyway. At least it was only $5 and I guess I'll know if they wired my harness correctly. Maybe the tester I ordered will be different from yours. Probably not, but I guess we'll see. Here's the one I got:

http://amzn.com/B0002Q7C3A
__________________
2011 X3 (F25) xDrive 35i 3.0L, nav, xm
Reply With Quote
  #8  
Old 06-27-2013, 12:32 PM
roadkillrob roadkillrob is online now
Officially Welcomed to the 'Fest
Location: Boston
 
Join Date: Aug 2006
Posts: 2,447
Mein Auto: 325CIC, 335CIC
Quote:
Originally Posted by invisihitch View Post
I wish I had seen this yesterday (or perhaps you can still cancel your order for the LED-based circuit tester). We use an LED tester here, and the LEDs do not provide enough resistance for the harness to sense that a trailer is plugged in.
I smell business opportunity - you guys should make one up with a little more resistance and sell it to us all!
__________________
2008 335i Vert Montego/Saddle/Grey Poplar
2014 X3 35i Space Grey/Chestnut/Fineline Wave
Reply With Quote
  #9  
Old 06-27-2013, 12:41 PM
SpaceManGray SpaceManGray is offline
Registered User
Location: Wisconsin
 
Join Date: Aug 2012
Posts: 88
Mein Auto: 2011 X3 35i
Quote:
Originally Posted by roadkillrob View Post
I smell business opportunity - you guys should make one up with a little more resistance and sell it to us all!
I was thinking the same thing. I'd be happy to pay for one. The question is, how much is it worth?

There was a user on the X5 forum that said he built one. The thread was pretty old but I bumped it... If he responds, I'll link to it here.
__________________
2011 X3 (F25) xDrive 35i 3.0L, nav, xm
Reply With Quote
  #10  
Old 06-27-2013, 01:00 PM
Coder Coder is offline
Officially Welcomed to the 'Fest
Location: Colorado Springs
 
Join Date: Feb 2012
Posts: 198
Mein Auto: 2011 X3 xDrive35i
Suggest you all mean you want something with less resistance, i.e., more current draw aka a greater load. I assume that the circuit is 12 volts and they are looking for a load similar to that provided by normal set of trailer light bulbs, say a few watts or more. You could probably verify this by hooking up a single auto/trailer marker light bulb or similar, see if you get the desired effect. Although it sounds like it might just turn off the camera entirely...

Or go to your local Radio Shack and get some resistors, say 100, 50, and 25 ohms. 100 ohms should provide about a 1.5 watt load, 50 should be close to 3 watts, and 25 should be nearly 6 watts. Make sure you get resistors with the required wattage capability. I'd go with at least 5 watts for the 100 and 50 ohm units and 10 watts for the 25 ohm piece. Try bending the leads or whatever you need to do to plug those into the harness. One should do the trick and it'll look just like a trailer light to the circuit.
__________________
Dave @7500 feet on the plains in Colorado
2011 X3 35i - Blue Water Metallic
Reply With Quote
  #11  
Old 06-27-2013, 01:59 PM
SpaceManGray SpaceManGray is offline
Registered User
Location: Wisconsin
 
Join Date: Aug 2012
Posts: 88
Mein Auto: 2011 X3 35i
Quote:
Originally Posted by Coder View Post
One should do the trick and it'll look just like a trailer light to the circuit.
Ya, that's what will probably end up happening. I'll get out the multimeter this weekend and see what kind of resistors I'll need to get. I wouldn't be surprised if it is similar to what is needed on turn/brake signal lines when regular bulbs are replaced with LED bulbs. (of course, we can code the F25 to recognize LED turns/brakes but not all vehicles can be)
__________________
2011 X3 (F25) xDrive 35i 3.0L, nav, xm
Reply With Quote
  #12  
Old 06-27-2013, 10:39 PM
Lou r Pitcher Lou r Pitcher is offline
Registered User
Location: Texas
 
Join Date: Jun 2013
Posts: 26
Mein Auto: X3
Anyone know what trailering actually does to the Vehicle Stability Control. The marketing literature for the BMW installed hitch says connecting a trailer notifies the VSC. But I have no indication anywhere in the dash that my connected trailer is ever detected. (I do not have the backup camera or backup sensors, so no hitch icon. ) Perhaps mine is not being detected?
Reply With Quote
  #13  
Old 06-30-2013, 08:34 AM
invisihitch invisihitch is offline
'Fest Sponsor
Location: Atlanta
 
Join Date: Nov 2012
Posts: 279
Mein Auto: 2012 X3
Quote:
Originally Posted by Lou r Pitcher View Post
Anyone know what trailering actually does to the Vehicle Stability Control. The marketing literature for the BMW installed hitch says connecting a trailer notifies the VSC. But I have no indication anywhere in the dash that my connected trailer is ever detected. (I do not have the backup camera or backup sensors, so no hitch icon. ) Perhaps mine is not being detected?
If your trailer lights are working correctly, that is a very good indication that the reprogramming processed correctly when hitch was added. So it's a good bet your trailer is detected when plugged in. I guess you could temporarily remove a bulb on your trailer to confirm that the harness and the vehicle are actively communicating. You should get a chime and a dash indicator of a malfunctioning trailer bulb. Lastly, if I recall correctly, the in-cabin hatch release should be disabled when a trailer is connected. So that may be another way to confirm that the harness and vehicle are communicating correctly (but catch the hatch before it hits anything!)

As for the workings of Stability Control when a trailer is detected, there is a yaw sensor in the far rear, driver's side of the vehicle. When a trailer is connected, monitoring is initiated for repetitive swaying ("trailer snaking"). A snaking trailer will put enough force, side-to-side, on the rear of the vehicle for the yaw sensor to detect that the rear of the vehicle has acquired a certain wave pattern side-to-side. At that point, stability control will step in and apply braking in a counteractive pattern to bring the trailer back under control. I don't recommend trying to "test" this feature.
Reply With Quote
  #14  
Old 06-30-2013, 12:11 PM
Lou r Pitcher Lou r Pitcher is offline
Registered User
Location: Texas
 
Join Date: Jun 2013
Posts: 26
Mein Auto: X3
Thank you for reply. My trailer lights ( all Leds) are lighting correctly but the bulb failure detection was not activating when a trailer turn signal wire is opened....no ding or any indicator is on dash. A road test with my connected trailer suggested DSC was fighting the trailer rather than helping control it.....it didn't know trailer was back there.

As a test, I paralleled an incandescent bulb across a trailer running light. All trailer lights still worked, but now if I open a turn signal circuit, I properly do get the ding and lamp failure message on the X3's dash. And the turn sigals flash very quickly. ( will also test the hatch lift disable later when I next have boat connected.)

This tells me that while my all LED trailer's lights can get power and work ok, the BMW system does not ever see the Led bulb as a load and never was informing my DSC of a trailer being connected.

I have just ordered a Euro VW/Porsche, 7pin to 7 pin adapter to further investigate and test. It places a resistive load across the Led running light circuit to load the circuit sufficiently that the BMW hopefully will sense the trailer's connection and inform the DSC to go into trailer mode. Will Post results......

Last edited by Lou r Pitcher; 06-30-2013 at 09:52 PM.
Reply With Quote
  #15  
Old 07-01-2013, 10:27 AM
invisihitch invisihitch is offline
'Fest Sponsor
Location: Atlanta
 
Join Date: Nov 2012
Posts: 279
Mein Auto: 2012 X3
For 100% LED trailers, I generally suggest replacing the two main lights on the rear of the trailer with incandescent taillight assemblies. They may not be as stylish as the LEDs, but you will activate ALL the functions of the wiring harness by doing this. Placing a resistance load at the 7-pin trailer receptacle can activate most functions (Stability Control, PDC silencing, etc) but at the same time it can actually prevent the detection & reporting of a taillight failure. Shorts/failures occur too frequently on boat trailers in particular, and it is nice to be informed by the dash indicator and chime as soon as a taillight stops functioning.

Just my $0.02
Reply With Quote
  #16  
Old 07-01-2013, 01:17 PM
Lou r Pitcher Lou r Pitcher is offline
Registered User
Location: Texas
 
Join Date: Jun 2013
Posts: 26
Mein Auto: X3
Incandescent bulbs fully replacing my boat trailer's Led is not an option....the custom molded housing is sealed and waterproof and we are talking about a $50,000 boat and trailer that you can't just bolt on any non-custom light fixtures.

Can though take the equivalent resistive load of the incandescent bulbs and accomplish getting the BMW to at least recognize the presence of the trailer. Light failures are very uncommon with these LEDs arrays and these boats have trailer wiring supplied with their own conduits that make circuit failures a non concern. Would much prefer having the BMW DSC safe and working than having a rare LED failure flagged.

Last edited by Lou r Pitcher; 07-01-2013 at 01:24 PM.
Reply With Quote
  #17  
Old 07-01-2013, 01:54 PM
invisihitch invisihitch is offline
'Fest Sponsor
Location: Atlanta
 
Join Date: Nov 2012
Posts: 279
Mein Auto: 2012 X3
I don't disagree with you. Unfortunately, you sometimes have to pick your poison when it comes to using an intelligent harness together with a trailer that has 100% LED lights.

It's not perfect, but the situation is a lot better now than it used to be. The early harnesses pulsed low-voltage signals a couple of times per second to test for bulb failures. The low-voltage signal was purposely not sufficient to light an incandescent bulb, but an LED trailer would flash constantly as you drove down the road!
Reply With Quote
  #18  
Old 07-01-2013, 02:48 PM
Lou r Pitcher Lou r Pitcher is offline
Registered User
Location: Texas
 
Join Date: Jun 2013
Posts: 26
Mein Auto: X3
My 2014X3 is indeed rapid pulsing the trailer harness circuits and yes the LEDs, without the additional load resistors, are visible (barely) flashing rapidly and constantly.

Last edited by Lou r Pitcher; 07-01-2013 at 02:54 PM.
Reply With Quote
  #19  
Old 07-01-2013, 07:21 PM
invisihitch invisihitch is offline
'Fest Sponsor
Location: Atlanta
 
Join Date: Nov 2012
Posts: 279
Mein Auto: 2012 X3
If the LED blinking continues after you insert resistance load at the trailer plug, you may want to ask your dealer to flash the harness' AHM module to bring it up to the latest firmware. You may get a blank stare, but it's worth asking. The LED blinking is nearly undetectable with the latest AHM firmware.
Reply With Quote
  #20  
Old 07-01-2013, 09:49 PM
Lou r Pitcher Lou r Pitcher is offline
Registered User
Location: Texas
 
Join Date: Jun 2013
Posts: 26
Mein Auto: X3
Thanks. I surely have whatever firmware BMW installed at the factory when car was made about 4 weeks ago.

Local dealer indicates they do not know/understand how the trailer is sensed by the X3 or how they or I can check to see if the X3 knows the trailer is even present.

At this point, by reading the various boards I am ahead of my service advisers in understanding the trailer hitch interfaces and how LEDs vs Incandescents affect sensing circuits.

Last edited by Lou r Pitcher; 07-01-2013 at 09:51 PM.
Reply With Quote
  #21  
Old 07-02-2013, 06:47 AM
invisihitch invisihitch is offline
'Fest Sponsor
Location: Atlanta
 
Join Date: Nov 2012
Posts: 279
Mein Auto: 2012 X3
Actually, you have whatever firmware Helbako flashed onto its AHM module back when it manufactured your particular AHM module. Helbako then shipped a batch of the modules to the wiring-loom manufacturer. The loom manufacturer then bundled your AHM module with one of its X3 trailer-harness looms and put a batch of them on a boat for North America. When it arrived, it was shipped to BMWNA's hitch manufacturer for the X3. It was staged there until the hitch manufacturer kitted it out with one of its hitches, boxed everything together, and shipped the complete hitch kit to one of BMWNA's parts-distribution warehouses where it gathered dust until your dealer's parts department placed a replenishment order for an X3 hitch. At that point it was shipped to your dealer and put on a parts shelf. Then, one day, the parts manager realized he only had one X3 hitch in stock so he ordered a couple more and... stacked them on top of yours. Hey they're heavy and they're all the same anyway right? Finally there was a big run on X3 hitches at your dealer, and your hitch (with its AHM module) got pulled off the bottom of the shelf and installed on your vehicle. I left out a few steps, but you get the idea. The revision dates on our AHM modules vary by two years or more.
Reply With Quote
  #22  
Old 07-03-2013, 10:52 PM
Lou r Pitcher Lou r Pitcher is offline
Registered User
Location: Texas
 
Join Date: Jun 2013
Posts: 26
Mein Auto: X3
For those with bike carriers and other trailer hitch loads with no lights that are wanting to simulate trailer presence by placing load resistors across their BMW trailer connector pins...

There is an adapter available on Amazon.com and other sources that does that in a 7pin flat female 7pin flat male configuration such that it does not physically change the BMW trailer connection other than adding the load resistors. It is marketed as for VWs, Porsche's, Mercedes, Audi's and other European autos used with LED trailers needing to be run from incandescent lamp fail sense auto electronics.

http://www.etrailer.com/Wiring/Tow-Ready/20142.html

There are 3 resistors and each is 100 ohms and located within the adapter. Each resistor is run from the ground pin to the respective left turn/brake, right turn/brake and running/license lighting pins.

Last edited by Lou r Pitcher; 07-03-2013 at 11:25 PM.
Reply With Quote
Reply

Bookmarks


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > X Series > X3 F25 (2011 - current)
Today's Posts Search
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On



Forum Jump


All times are GMT -7. The time now is 04:38 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
© 2001-2011 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms