[TOF12]

Hi,

I've discovered this topic with delight as I've bought a second hand electric oem tow bar with the donor car wiring. The donor car must be a pre lci whereas mine is a e91 from 2011 with rear parking sensors.
I got both modules from the donor car. AHM module must be a AHM3.

I've followed the wiring instructions from the latest retrofit instructions that was kindly shared on this forum. As my module is a AHM3 I do not need the red and yellow cable that should be connected to fuse 71.
My car fuse label gives 4 points to connect the red cables: 24, 31 and 32.
I've connected the yellow and black cable using the BMW miniature connector near the floor module connector on the cable coming out pin 40 as instructed in the retrofit document.
Green and black cables is inserted in pin10 of the CAS module.
Twisted green, green and orange cables are connected in the boot.

After connecting the battery again 2 errors came up the first concerns the 4wheel drive management system and the dsc. The second concerns the exterior lights, none of them are working (headlights, taillights, indicators, door lights).
The two bar activation bouton has no light and pressing it does not lead to any action.
I' ve decided to unconnected everything I had added to the car and now I still have both errors.

Did you have those sort of problems during your installation?
Could you explain what modification you did to your pre lci wiring to fit your lci harness?

Thanks a lot, to be honest I'm a bit desperate as I don't understand what the problem might be and hope I did not damage the FRM modul.
Thanks

[Andystobbs]

I didn't have any such difficulties. Can you read the actual errors diagnostically?

[TOF12]

Thanks for your answer.

Unfortunately no, I've no diagnostic tools. But I might try to find someone that can read it.

Have someone manage to get the tow bar out by feeding it with 12v directly?

[Andystobbs]

The AHV module only needs one 12v feed from memory and ground ofcourse. The button for towbar deployment/retraction is only functional when tailgate is open and ignition off. Seem to recall the CAS does ignition signal on green/black and tailgate via FRM on yellow/black. The LED on the button will not illuminate outside those parameters.

[WWPearlMS6]

Lots of good info here

[Bean801]

Hello all, I apologise in advance for the long thread.
I’m hoping someone here might be able to help me.
I have brought a second hand OEM folding tow bar with modules from a breaker.
My car is a 2008 E91 320d Msport.
I have no issues with the mechanical side of things but I am lost when it comes to the wiring.

I have looked at the retro fit guide but I just can’t get my head around it. Probably not helped by the cut loom I have received.

I have taken some pictures but I don’t know how to upload them?

My questions are about where the cut wires should go?

So I’ll begin
The first branch of wires come out just after the grommet that goes through into the boot. There are 5 wires in this branch that are just cut
Blue with brown trace
Thick brown
Grey with blue trace
Yellow with purple trace
Black with blue trace

The second set of cut wires come out of the main loom after the first branch of 5 wires. Here there are 9 cut wires
4 x Brown (2 x thick & 2 x medium thickness)
Red with blue trace (thick)
Yellow with purple trace
Grey with blue trace
Blue with brown trace
Black with blue trace

Next set come from the AHM module that has a black plug
Here I have 7 cut wires
Red with purple trace (thick)
Red with yellow trace (thick)
Brown
Blue with brown trace
Black with yellow trace
Green and orange with green trace twisted together

Next set come from the AHV module that had a white plug
Here I have 8 cut wires
Red with black trace (thick ish wire)
Brown
Green with black trace
White with brown trace
Blue with brown trace
Blue with white trace
Blue with green trace
Blue with black trace

The last set are from the switch
There are 4 wires here
Blue with brown trace
Blue with white trace
Blue with green trace
Blue with black trace
I’m assuming that the 4 wires from the switch should be connected to the corresponding wires that I have coming from the AHV module.

I’m also assuming that the brown wires should all be earthed?

It’s just the rest that I’m not sure of.
Any help would be greatly appreciated

[Bean801]

https://share.icloud.com/photos/0NgW...MI_bZpNXQ#Home

Link to my pictures if it helps.

I’ve tried everywhere I can think of for help but nowhere is prepared to take on the job.

Can anyone help???

[Bean801]

Originally Posted by Scoff123

Thanks! Interesting - that is a different version of the PDF to the one that I have - your file is newer, produced 09/2012.
My instructions were procuded 07/2007 and I couldn't find anything newer. Here is my document
https://www.dropbox.com/s/qj6h8gfsj3...ation.pdf?dl=0

I'll have a read through your instructions and see if there is much different after 2007 - it's been a bit tricky adapting a 2005 loom and modules to my 2011 car's wiring making sure i'm connecting to the right fusebox locations. Wish i had just bought the physical crash bar and hitch on it's own and bought the wiring kit new from BMW and got the latest loom to match my cars wiring - oh well, live and learn. Hopefully it will all work out though and then we can get the coding sorted!

If the connector i've ordered from BMW isn't the right size for the green 15 pin fusebox plug, i'll give you a shout as you might have the right one in the remains of your kit.

I don’t suppose you still have a copy of the retrofit instructions? If you have is there any chance you could send me a copy. I think my loom might be the older one that you guide could help me decipher.

[jamesfawcett]

Originally Posted by Bean801

I don’t suppose you still have a copy of the retrofit instructions? If you have is there any chance you could send me a copy. I think my loom might be the older one that you guide could help me decipher.

Here you go hope this helps: https://www.dropbox.com/s/mpigspa0m3...tions.pdf?dl=0

[Bean801]

Originally Posted by jamesfawcett

Here you go hope this helps: https://www.dropbox.com/s/mpigspa0m3...tions.pdf?dl=0

Thanks for the guide, unfortunately that is the one I’ve already got.

[jamesfawcett]

Oh that's a shame

Fitting the retrofit wiring kit was enough of a faff, I wouldn't like to be doing what your doing to get it working Makes the price of the retrofit kit from BMW seem worth every penny!

[Bean801]

Originally Posted by jamesfawcett

Oh that's a shame

Fitting the retrofit wiring kit was enough of a faff, I wouldn't like to be doing what your doing to get it working Makes the price of the retrofit kit from BMW seem worth every penny!

I’ve tried everywhere I can but the retro fit kit just isn’t available anymore more.

I’m getting to the point where I think I’m going to have to cut my losses and get a detachable bar

[Scoff123]

Sorry to hear you are struggling. Here is my older version of the retrofit instructions which were published in 2007

https://www.dropbox.com/s/sqqw6upw3z...ation.pdf?dl=0

What year was the breaker car that you got the parts and cut loom from?
Do you have access to ISTA which contains all the electrical wiring diagrams for the relevant parts of the loom and modules, which shows wire colours and pin numbers etc?

I'm going to have to revisit my installation as my bar has stopped releasing resulting in a flashing red light. I had this during initial fitment, although now it sounds like the motor is struggling and not able to release my bar
My battery has been struggling the past 2 or 3 winters so wondering if it just doesn't have the oomph required for the large current required by the motor to release the arm. Either that or my AHK module is faulty, or maybe even something inside the motor itself is stuck/faulty. Going to have to get the rear bumper off and see what's going on. Then time to get the front bumper off to replace my aircon condenser which has sprung a leak. Always something!

[Bean801]

Originally Posted by Scoff123

Sorry to hear you are struggling. Here is my older version of the retrofit instructions which were published in 2007

https://www.dropbox.com/s/sqqw6upw3z...ation.pdf?dl=0

What year was the breaker car that you got the parts and cut loom from?
Do you have access to ISTA which contains all the electrical wiring diagrams for the relevant parts of the loom and modules, which shows wire colours and pin numbers etc?

I'm going to have to revisit my installation as my bar has stopped releasing resulting in a flashing red light. I had this during initial fitment, although now it sounds like the motor is struggling and not able to release my bar
My battery has been struggling the past 2 or 3 winters so wondering if it just doesn't have the oomph required for the large current required by the motor to release the arm. Either that or my AHK module is faulty, or maybe even something inside the motor itself is stuck/faulty. Going to have to get the rear bumper off and see what's going on. Then time to get the front bumper off to replace my aircon condenser which has sprung a leak. Always something!

Many thanks for that.
The loom looks much the same as in the newer retrofit instructions.
Neither of the instructions show the branch of 5 wires that comes out just after the grommet where it passes into the boot that I have on my loom.
The breakers I got the bar and loom from said it was removed from a 2007 E91 320d. So I assumed that would be perfect for mine as it’s a 2008 320d pre lci.

I left the motor trade about 8 years ago. I don’t have access to ISTA or any wiring diagrams. I worked with mainly historic racers so this level of wiring was never something that I dealt with. Give me a simple wired car with a dizzy and I’m fine.

I have asked fast fit who are local to me and been to an auto electrics that usually have no issue with any electrics but both were not happy to attempt it.

[Scoff123]

No problem! I'll go through some of the pictures I took during my retrofit and see if they might be of any use. Failing that, when I get my rear bumper off to investigate my issue, I should be able to help identify at least some of those wires and where they go on my car. My car is a 2011 LCI but I think a lot of the wiring should be the same as the pre-lci in regards to the towbar end of the loom at least. I'll also have a look on ISTA and see if there are some wiring diagrams for your year of car that might be helpful - if you want to PM me the last 7 digits of your chassis number I can make sure I'm looking at the correct build diagrams etc 👍

[Bean801]

Originally Posted by Scoff123

No problem! I'll go through some of the pictures I took during my retrofit and see if they might be of any use. Failing that, when I get my rear bumper off to investigate my issue, I should be able to help identify at least some of those wires and where they go on my car. My car is a 2011 LCI but I think a lot of the wiring should be the same as the pre-lci in regards to the towbar end of the loom at least. I'll also have a look on ISTA and see if there are some wiring diagrams for your year of car that might be helpful - if you want to PM me the last 7 digits of your chassis number I can make sure I'm looking at the correct build diagrams etc 👍

That would be brilliant if you could.
I’ll pm the classic no shortly.

Time is on my side at the moment. Don’t need to tow anything until next year.
If you get some pics of where the branches go out and I can identify where the front branch should be I might stand half a chance.
Thank you

[Andystobbs]

Hope this comes out well, I'm posting from my phone.

Will start with the AHV module wiring as this is same module across all years and models.

Pin 1 White/Blue 1.5mm2
Pin 7 White/Red 0.35mm2
Pin 9 White/Green 0.35mm2
Pin 10 White/Yellow 0.35mm2

All go to the actual swinging motor part of the towbar, plus a Brown Earth coming back, to be grounded inside the car.

Pin 12 White/Brown is tailgate contact switch, you'll find this at the tailgate lights.
This enables the operation of the towbar when tailgate is open.

Pins 5,6,14,15 all go to the towbar extension / retraction button as you say. Simply connect like colours.

Pin 11 Green / Black is ignition on from CAS. Pin 10 X13376

Pin 2 is main power F10 15A in junction box
Pin 4 is contol Unit Earth
Pin 13 loops to AHM module and provides a coded signal for evaluating the hitch position.

[Andystobbs]

Plug X13376 at CAS

[Andystobbs]

For the AHM wiring I'll need some info from you. The different versions have different Pinouts.

Can you find which pin numbers your Red/violet and Red/yellow wires go to in the AHM plug and report back.

[Bean801]

Originally Posted by Andystobbs

For the AHM wiring I'll need some info from you. The different versions have different Pinouts.

Can you find which pin numbers your Red/violet and Red/yellow wires go to in the AHM plug and report back.

Many thanks for the information.

I will get some pictures of the plugs etc tomorrow.
How do i identify the pin no's on the plugs? Are they marked on the plug or is there a different way to confirm the pin no's?

Thank you for your help

[Bean801]

Here is a link to some pics
https://share.icloud.com/photos/0bIX...smzszcXjeTDKXA

The first pic with the battery in view & the mass of cut wires shows the first small branch of 5 wires.
The remaining 9 come out approx 1 inch after the first.
The first branch of 5 wires are all in the second branch of 9. I am wondering if these wires are anything to do with the actual tow bar and if they were maybe for the rear light on the original donor car?
If i removed these out of the equation this would leave 3 brown wires & 1 thick red with blue trace.
3 brown for earth & 1 permanent live from the battery maybe?

This would then just leave the wires from the 2 modules to connect.

The second picture shows both the modules with the cut wires & the 3rd picture shows the complete loom from after it passes into the boot.

I will get a closer look at the plugs/wire positions tomorrow.

Thanks for trying to assist me. Any help is greatly appreciated.

[Scoff123]

OK so it's a million degrees outside so I'm having to do a few minutes then come indoors to cool down lol but starting with:

"The first branch of wires come out just after the grommet that goes through into the boot. There are 5 wires in this branch that are just cut
Blue with brown trace
Thick brown
Grey with blue trace
Yellow with purple trace
Black with blue trace"

These are all the wires that go to your rear light cluster normally, so for now you can disregard these 5 as they are already present in your car. Once we know that the remainder of the loom that runs to the front of the car is complete, then these 5 wires can be stripped out of your loom as they are not needed. Here are those same wires on my car light cluster



Looking at the 2 modules next, here are the wiring diagrams based on your own vehicle VIN number, showing the wire colours which might help

AHM - Trailer Module for trailer lighting



AHK / AHV - Towing Hitch Release Module



Will report back with further info after I've had a cold beverage and stopped sweating so much