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Let's DIY aux input cable.

861019 Views 805 Replies 319 Participants Last post by  Auxburgo
This is not how to install aux input cable rather how to make it.
Seriously, I don't want to spend about $50 for a stinking cable.
I'm in Canada and usually BMW parts are more expensive than US.

Let's get started.

1. This was male on both end and I just cut one side.

2. Close up

3. Some people might wonder what this is.

This is a cable that I found from my old computer I was about to throw away. This pin connects to motherboard for power switch, reset switch, hdd led, power led, etc.
Do not cut the other end of this cable, just pull the pins out. It will help you to solder it. :)

4. See? It is so much easier to connect them to solder it.

5. 3 small and 1 big heat shrink tube.

6. Ok. It is done.

7. From HU, pin 8,9(left,right or right,left don't care too much. :D ) and pin 4(ground) need to be connected.
You will be surprised how well it fits. :D

8. Finished

Total cost $0. Because I found everthing I need at home and it works great. :D
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I seem to remember somebody mentioning trying smaller capacitors(?)

Has anyone tried that yet?
red/black(sound left/right) goes into pin 8/9 and
yellow(grounding) into pin 4.

if you take the deck out and look close into it, it has numbers.
Heyy frist of all, thanks a lot for The further explaining of how to connect the wires.
I have a problem because i have connected the 3 wires on pin 8 and 9 and 4 but when I press the mode button, the aux option dous not show... what do i have to do? Disconect battery?

Kind regards from the Netherlands!
You have to have something drawing to get the radio to see it.
A capacitor or something similar usually has to be installed for the radio to recognize somethings there.
Most of the ones bought online come with something inline to draw a current.
Hi all.
Can anyone help me please, I'm new to this and I'm not sure if I got it right.
Car is 3 series 04 plate
At first I just put the 3 wires in ground in 4 left and right in 8 and 9 and got nothing, I then splice the left and right and put a 300k resistor across the left and right.
I plug it in and now I get the aux when press mode, As soon as I plug my phone in the jack it will switch back to radio, the phone was powered by its own battery not on charge.
I then cut the left and right wires and put 0.22uf capacitors on the left and the right wires. I have the resistor at the head unit end of the wires, I get nothing again.
Did I need to splice the wires for the capacitors or cut them and put them in?
I get continuity from the jack to one side of the capacitors and from the other side of the capacitors I get continuity to the plug to the HU.
I do not get continuity from the jack to the plug, but I think that is right because of the capacitors?
What did I do wrong?
Thanks Ian.
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You can buy those all day from eBay for under $10 ($15 with shipping).
Thats the direction i would tell you to go.
Thanks rvaughnp i can buy them from banggood for £3. I just wanted to try to do it myself with the bits I had hanging around.
Thanks anyway Ian.
I hear you. I did the same. Spent about 2 hrs researching, 1 HR to and from RS. 1 HR building and 1/2 HR of install to find my dyi that didn't work. Another HR reaching on why it wasn't working.
Verses 15 mins on eBay, 1/2 HR install and tada.
ok I'm sold I just ordered it, ill post my findings when it gets here.
Thanks again Ian.
Not sure why you guys had issues. I DIY'd mine with some old scrap parts and wiring I had laying around. I did the basic version, sans any resistors or caps (as of yet) more or less just to verify that I could get it working at all. The fact that aux disappears and the head unit defaults to other input sources began annoying me right away tho so I considered adding the "pre-load" components. Although I think ultimately I'm hoping to find a simple and affordable Bluetooth interface.
ok I'm sold I just ordered it, ill post my findings when it gets here.
Thanks again Ian.
Assuming you got the one one that has no outer clip...
It can be a bugger to put in. Just a little tight. Make sure to look at the wire connection pic and put a colored dot on one side or the other of the end going to the radio to line up the speaker wires. "Top or bottom".
How do you know that your radio supports Aux

HI all I have a Siemens radio 6512 6916047-02 on my 2003 E46 and I'm keen to install the aux cable on it but I'm not sure if this radio has the aux supported, can somebody help me please?
If I put in the aux cable, will I still be able to use my cd changer in the trunk? Or will I lose the cd changer option?
My 2004 316i says this on the radio "SV 18-04 600". Can someone tell if this supports AUX. I'm assuming it does not since I tried and it didn't work. Thanks.
Assuming you got the one one that has no outer clip...
It can be a bugger to put in. Just a little tight. Make sure to look at the wire connection pic and put a colored dot on one side or the other of the end going to the radio to line up the speaker wires. "Top or bottom".
Thanks rvaughnp I got the 1 with the little arrow on top works fine.
2002 Siemens Radios doesn't support aux

Dear all, I phoned the dealer and through the VIN number of my 2003 E46 I gave them, they could confirm that my Siemens radio doesn't support aux as the car was built at the end of 2002. Then as an alternative I got a FM transmitter for £6 to reproduce my music from my mobile phone. Not the best quality sound but it works...
Old thread but I figured I'd update this a little.

Obviously you cannot charge and play simultaneously if you follow the instructions on the first page.
The problem has already been solved but building a Ground loop isolator... when you could go to radio shack and buy one. I mean most of us would probably end up there to purchase the items you need to make one... Credits to
I use my AUX in with iPhone 3G-S 32G everyday.

To charge, you need to install a Ground-Loop Isolator in the audio line.
Isnt there a snowcat87 on youtube... Same person:hmm:

Add this

between this

and this


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Slight resurrection for clarity sake. To save others trawling through the thread, here's a summary based on my research.
the E46 is capable of adding an AUX port, depending on the model of the Business CD head unit installed. In general terms 2004 onwards should be compatible. The only way to know for sure though is to check the part number of the actual radio. It's relatively easy to remove.
The below list explains the compatibility:
1998 to 2001 E46 3 Series vehicles

Blaupunkt, Part Number 6512-6 909 883 iPod Data Capable
Blaupunkt, Part Number 6512-6 909 882 iPod Data Capable
Blaupunkt, Part Number 6512-6 902 661 iPod Data Capable

NOTE: iPod Data Capable is ONLY if the car is Prewired in the trunk for the CD Changer - You can also add Aux Input ONLY thru an iPod Data Kit like the USA Spec PA12 or the DICE iPod kits

2001 to 2007 E46 3 Series vehicles including the E46 M3

Alpine, Model CD53, Part Number 65. 12-6 916 241 (July 2001) iPod Data Capable
Alpine, Model CD53, Part Number 65. 12-6 915 711 (Sep 2001) Ipod Data Capable

Alpine, Model CD53, Part Number 65. 12-6 919 072 (Dec 2001-Jun 2002)iPod Data, Sirius Capable
Alpine, Model CD53, Part Number 65. 12-6 921 963 (July 2002-Jan 2003)iPod Data, Sirius Capable

Alpine, Model CD53, Part Number 65. 12-6 927 902 (Feb 2003-Aug 2003)iPod Data, Aux and Sirius Capable
Alpine, Model CD53, Part Number 65. 10-6 927 903 (RMFD thru Dec 2006) iPod Data, Aux and Sirius Capable
Alpine, Model CD53, Part Number 65. 12-6 941 505 (Jan 2004 - Sept 2004) iPod Data, Aux and Sirius Capable
Alpine, Model CD53, Part Number 65. 12-6 941 506 (RMFD thru Dec 2007) iPod Data, Aux and Sirius Capable

Alpine, Model CD53, Part Number 65. 12-6 943 429 (Oct 2004 -Sept 2005) iPod Data, Aux, Sirius and MP3 Capable
Alpine, Model CD53, Part Number 65. 12-6 943 430 (RMFD thru 2008) iPod Data, Aux, Sirius and MP3 Capable
Alpine, Model CD53, Part Number 65. 12-6 961 215 (Dec 2005-May 2006) iPod Data, Aux, Sirius and MP3 Capable

NOTE: RMFD = Re-manufactured/Refurbished.
If you find any BMW Business CD53 Radio Unit with a production year date sticker on it that is later than these production dates corresponding to each part number unit (IE. a year date that is 05, 06, 07, 08) it is most certain that those units are re-manufactured/refurbished (RFMD) under warranty and re-labeled to reflect the date of re-manufacture. This is especially true for the factory recalled MP3-capable BMW Part Number 65. 12-6 943 429 unit which is always re-labeled to become BMW Part Number 65. 12-6 943 430 after refurbishment.


If you have a compatible CD you can either DIY your own cable based on this thread or buy an OEM cable (expensive) or look on ebay for a non-genuine cable. One quirk of the CD setup is that in the majority of cases, the cable on it's own will work to display the AUX input mode ONLY when you have an active source connected to the unit and only if you are NOT using the cigarette lighter to charge anything. As soon as you connect a charger to the cig lighter, it creates a ground loop and AUX is disabled. The workaround is to incorporate a 330k ohm 1W resistor joining the left and right stereo cables and then add a 220um capacitor separately on each of the stereo wires.
Doing this will set the AUX circuit up so that the AUX option is always visible in the cd units mode's (even if nothing is connected) and you are able to charge at the same time. A great simple guide is here:

Finally, a word of warning. Many of the non-genuine cables purchased off ebay lack the capacitors and resistors. These will work, but only when AUX input is connected and a charger is not. This is what I ended up with. The good news is that it's easy enough to open the ebay cable and solder in a resistor and capacitor to get the best of both worlds. The advantage of this is the molex style pins at the stereo end are already configured for you, there's a female AUX port at the other end all wired up. For me I peeled the heatshrink off the aux plug end to check the wiring. Mine had four wires: red and white stereo wires (left and right), a black ground wire and a green wire that was not connected to anything. Once you've confirmed this, heatshrink the cable back up, go about halfway down the cable and carefully slice open the cable wrap. Slice enough of the wire wrap away to enable you to pull out 4 or 5 cm's of the inner wires. Pull the red and white (or whichever colour is the stereo on yours) wires free and snip them. You then solder the resistor across these two wires (at the CD unit end of the split, not the aux end) I then soldered on to the red and white wires, after the resistor, an extra cm of 26 gauge wire i had to give me a bit of room to move. take your capacitors then and solder to either side of the red wire, do the same with the white. The result should be the molex connector at one end, halfway along the cable there's a resistor bridging the red and white stereo wires, then each stereo wire continues through a capacitor and back into the wire wrap to the aux at the other end. Generously heatshrink the connections, wrap with electrical tape and you end up with a fully functional aux cable for very cheap (ebay non-genuine cable was $6, resistors and capacitors were less than a dollar each).
I ended up drilling a small (6.5mm) hole in the trim piece between the stereo and the steering wheel (which is one of the pieces you are removing anyways to extract the stereo) and screwed the AUX port into that. The cable easily feeds through gaps behind the dash to come out in just the right spot. I then have an AUX port on the drivers side of the dash, just next to the steering wheel. I am able to connect a bluetooth wireless unit ( I use the Anker Soundsync) to the AUX and power off the cig lighter. I can mount my phone on the dashboard, in easy reach and view for screen control or GPS, and the Anker unit allows me to control functions (incl Siri) from the small puck glued to the dash right next to the AUX. easy as pie... eventually!_nr_
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I have read the entire thread. Great contributions and write up.

However, I have several questions that were also asked by several people, but no one replied directly. So here they are:

- I have unit with a CD button, what are my options?
- the unit is a 65.12-6 900 605
- it has wiring for a CD changer
- but there is no physical CD changer in the trunk.
- there is only 1 set of 10 pins on the back of the HU. It is for the CD changer.
- there is no AUX port.
- how can I make HU think that the BT unit (which is plugged into the CD changer port at the back of the HU) is the CD changer?
- the HU has what looks like 2 "antenna" plug in.
- if I change to a newer HU, what do I do about the antennas?

Any idea would be appreciated.


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Has there ever been a firm consensus on whether or not the resistor/capacitor trick kills bass response? I haven't done the trick yet but probably won't if the result is compromised bass response.
I guess I'm in a habit of resurrecting old threads recently, but I've bought a cable but I'm not seeing any AUX on my CD53 unit.
Car is built in November of 2001 and contains a BMW Business CD unit with MODE button.
In their ad it says: “This cable will enable AUX mode on your August 2002 or later Business CD head-unit.", which might be explaining the situation.

I've read that some of the cables require 100kOhm capacitor and 0,22microFarads resistors.

Looking for some help in resolving this problem. Appreciate any replies or hints how to fix it.

This is the cable: https://www.aliexpress.com/item/Aud...40654970.html?spm=2114.search0302.4.13.VU1AYG

One side note. I think some time ago I've might have seen AUX label appear when selecting MODE. However I haven't seen it for some time now and I'm not getting AUX option now.
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