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-   -   Auxiliary Audio Input Retrofit (Questions...) (http://www.bimmerfest.com/forums/showthread.php?t=76934)

nitram_luap 10-30-2004 07:28 PM

Auxiliary Audio Input Retrofit (Questions...)
 
Hello,

I have a 2004 E46 with Navigation and I'm looking at installing the AUX input retrofit.
http://www.bmwmotorsports.org/crew/u...stallation.pdf

I've removed the dash a/c vents and after much searching & unwrapping I've located the plug for which the AUX harness plugs into (I'm yet to buy the harness). It has 3 wires going into a little black plug (which resembles X14118). I can't imagine what else this is for.

My display currently does not display AUX when I cycle through the MODE button on the screen - only CD & Radio. (I have no CD changer so CDC is not present)

My questions:
- Will AUX *only* appear when cycling the MODE when there is a signal on that cable?
- Should AUX be there already if this retrofit is possible?

The reason I ask is because if this is not going to work, I'm not going to bother buying the AUX cable.

Any advice would be greatly appreciated. Thanks.

Paul Martin
Australia

nickeltong 10-30-2004 07:43 PM

Quote:

Originally Posted by nitram_luap
Hello,

I have a 2004 E46 with Navigation and I'm looking at installing the AUX input retrofit.
http://www.bmwmotorsports.org/crew/u...stallation.pdf

I've removed the dash a/c vents and after much searching & unwrapping I've located the plug for which the AUX harness plugs into (I'm yet to buy the harness). It has 3 wires going into a little black plug (which resembles X14118). I can't imagine what else this is for.

My display currently does not display AUX when I cycle through the MODE button on the screen - only CD & Radio. (I have no CD changer)

My questions:
- Will AUX *only* appear when cycling the MODE when there is a signal on that cable?
- Should AUX be there already if this retrofit is possible?

The reason I ask is because if this is not going to work, I'm not going to bother buying the AUX cable.

Any advice would be greatly appreciated. Thanks.

Paul Martin
Australia

The CD mode refers to your in dash CD. When you have the Aux-in installed, you should have a new AUX mode when you cycle the MODE button. In absence of the Aux-in install, the AUX mode does not appear. I had mine installed professionally so I don't know if there was any tinkering with the GM to have it recognise the Aux connection (although I highly doubt it).

nitram_luap 10-30-2004 08:02 PM

Quote:

Originally Posted by nickeltong
The CD mode refers to your in dash CD. When you have the Aux-in installed, you should have a new AUX mode when you cycle the MODE button. In absence of the Aux-in install, the AUX mode does not appear. I had mine installed professionally so I don't know if there was any tinkering with the GM to have it recognise the Aux connection (although I highly doubt it).


Thanks for the rapid reply!

Do you have AUX as an option when cycling MODE if there is nothing playing on the AUX line - or does it not show in this case?

The reason I ask is because if you look at the install (which requires no recoding apparently), the AUX harness is nothing more than an extension cable with a female 3.5mm socket at the other end. I can't see how the system would see it any differently to how it is seen now... 3 wires with nothing plugged into them.

The actual installation of the wiring is a piece of cake - it's the rest I'm not sure about.

The instructions (in the PDF file linked in my original post) state this in the 'Concluding Work' section.

- Conduct a brief test with DIS/GT1
- Conduct a function test

Could it mean that even though it does not require 'coding' as such, the dealer still needs to 'enable' AUX input on my stereo somehow?

Thanks,

Paul

nitram_luap 10-31-2004 01:41 AM

1 Attachment(s)
Quote:

Originally Posted by nitram_luap
...the AUX harness is nothing more than an extension cable with a female 3.5mm socket at the other end. I can't see how the system would see it any differently to how it is seen now...

OK... I'm officially an idiot! :rolleyes:

On closer inspection the harness is not quite JUST an extension cable. At the end of the install document is a circuit which (when I looked at it properly) shows a small resistor in the circuit between the L & R channel wires. That's how it *knows* that the AUX cable is connected!

I decided to test this out. I deliberately shortcircuited the L & R channel wires as they come out of the wiring harness and voila! - AUX now shows up when cycling the MODE button. When I remove the short, AUX disappears!

Now... all I need to do is buy about $3 worth of plugs, wire and the required 300kOhm resistor and I can make my own harness (for about 1/20th of the price of the BMW one!)

Excellent! :thumbup:

Paul

nitram_luap 11-01-2004 12:27 AM

I did it!

I bought about $4 worth of gear - wire, plugs & the resistor - and made my own wiring harness for the AUX in - and it WORKS perfectly!!

At first it was very quiet when plugged in, no matter how loud my devices volume was - then I noticed a little P1 in the corner of the screen which shows AUX on it.

When I pressed the buttons (numbered 1-6) beneath the MODE button I found out that this controls the input 'volume' - P6 is the loudest.

Now the AUX volume matches the volume on the other audio sources :)

All the wiring is hidden in the dash and the plug comes out in the glovebox - you wouldn't even know it was there!

:bigpimp:

Paul Martin
Australia

Technic 11-01-2004 03:26 AM

Quote:

Originally Posted by nitram_luap
I did it!

I bought about $4 worth of gear - wire, plugs & the resistor - and made my own wiring harness for the AUX in - and it WORKS perfectly!!

At first it was very quiet when plugged in, no matter how loud my devices volume was - then I noticed a little P1 in the corner of the screen which shows AUX on it.

When I pressed the buttons (numbered 1-6) beneath the MODE button I found out that this controls the input 'volume' - P6 is the loudest.

Now the AUX volume matches the volume on the other audio sources :)

All the wiring is hidden in the dash and the plug comes out in the glovebox - you wouldn't even know it was there!

:bigpimp:

Paul Martin
Australia

This is a great "reverse engineering on the cheap"... :D

What about the DC blocking caps (.22f) in the schematics? Did you install them? I do not see where you mentioned them. :eeps:

nitram_luap 11-01-2004 03:59 AM

Quote:

Originally Posted by Technic
This is a great "reverse engineering on the cheap"... :D

What about the DC blocking caps (.22f) in the schematics? Did you install them? I do not see where you mentioned them. :eeps:

Umm... whoops... :confused: I missed those completely!

I misread the -//- as 'continuation brackets' to signify a 'long cable' not capacitors (which they clearly are!!). I assume they are 0.22 Faraday capacitors?

The cable works flawlessly - been running it for the past hour to check - all seems well. What would those two capacitors do in that part of the circuit?

I'm very much an novice electrical engineer, but it's not too late to wire them in...

Paul Martin
Australia

Technic 11-01-2004 04:47 AM

Quote:

Originally Posted by nitram_luap
Umm... whoops... :confused: I missed those completely!

I misread the -//- as 'continuation brackets' to signify a 'long cable' not capacitors (which they clearly are!!). I assume they are 0.22 Faraday capacitors?

The cable works flawlessly - been running it for the past hour to check - all seems well. What would those two capacitors do in that part of the circuit?

I'm very much an novice electrical engineer, but it's not too late to wire them in...

Paul Martin
Australia

They are to block any DC that can get into the audio AC signal for circuit protection... you should install them ASAP. :thumbup:

nitram_luap 11-01-2004 05:03 AM

Quote:

Originally Posted by Technic
They are to block any DC that can get into the audio AC signal for circuit protection... you should install them ASAP. :thumbup:

Will do! Thanks! :)

Paul

Daver 11-01-2004 02:22 PM

Quote:

Originally Posted by nitram_luap
I did it!

I bought about $4 worth of gear - wire, plugs & the resistor - and made my own wiring harness for the AUX in - and it WORKS perfectly!!

At first it was very quiet when plugged in, no matter how loud my devices volume was - then I noticed a little P1 in the corner of the screen which shows AUX on it.

When I pressed the buttons (numbered 1-6) beneath the MODE button I found out that this controls the input 'volume' - P6 is the loudest.

Now the AUX volume matches the volume on the other audio sources :)

All the wiring is hidden in the dash and the plug comes out in the glovebox - you wouldn't even know it was there!

:bigpimp:

Paul Martin
Australia

Can you provide any specific part #'s for the BMW-end of the harness... the plug/socket/pins? Everything else, wires, resistors, caps, phono-jack should be readily available at most electronics supply houses.

Thanks!

nickeltong 11-01-2004 05:54 PM

Congrats Paul.

I've been away so I couldn't reply to your message. I guess you've found your answer and more. Maybe with some more tinkering, you can engineer an "AussieLink" and make some money with it ;) .

dkl 11-01-2004 08:53 PM

I don't think they are 0.22 Farads as those would be huge! As reference, a 1 Farad capacitor would be almost the size of a soda can. I think it's either 22 microFarads or 220 microFarads. Assuming that the line out impedance is 10K ohms, 220uF would be an overkill...heck, even 22uF is an overkill as the 10K, 22uF combo will pass frequencies down to 4.5Hz! But since line out impedance aren't always exactly 10K, the 22uF would be a safe value to use as your blocking caps.

nitram_luap 11-01-2004 11:36 PM

Quote:

Originally Posted by dkl
I don't think they are 0.22 Farads as those would be huge! As reference, a 1 Farad capacitor would be almost the size of a soda can. I think it's either 22 microFarads or 220 microFarads. Assuming that the line out impedance is 10K ohms, 220uF would be an overkill...heck, even 22uF is an overkill as the 10K, 22uF combo will pass frequencies down to 4.5Hz! But since line out impedance aren't always exactly 10K, the 22uF would be a safe value to use as your blocking caps.

Thanks for the info.

As blocking caps what are they protecting, the stereo or the device plugged into it?

I've just bought some 0.22F capacitors from my local electronics shop (they were 20c each) and they are pretty tiny. I'll post pictures of them (and of the BMW end of the plug) in another post.

Paul Martin

nitram_luap 11-02-2004 12:24 AM

5 Attachment(s)
OK... Here are the 'parts'

These were all found at my local electronics store (Dick Smith's)

- Stereo Audio Cable (1 metre) (I found a nice round black cable)
- 3.5mm stereo female socket (x1)
- 3 pin plug (see pictures) (x1)
- Resistor 300kOhm (x1)
- Capacitors (I've bought 0.22F ones - yet to be tested) x2

You'll also need some heat shrink & a good soldering iron. The actual assembly is pretty clear looking at the diagrams on the PDF file.

The 3 pin plug fits PERFECTLY into the BMW harness and due to the plastic 'guide' it will only plug in one way. I'm not sure what it is exactly but I found it in the electronics parts section...

Steps:

1) Remove passenger trim gently (an old credit card is excellent to gently pry out the friction pins - there are 4 of them on this trim)
2) Remove the Trim from above the monitor (should be one remaining friction pin close to steering wheel). This trim 'shares' a friction pin with the passenger trim. There is also a clip (just pull out) above the centre of the screen on this trim piece.
3) Unscrew the 2 screws from the top of the screen which also hold the a/c vents.
4) Pull out the a/c vents (they just go click, click like a ratchit - they push in the same way)
5) You should be able to see the wiring harness
6) The 'female' plug for the AUX input is hidden, wrapped up in that cable fabric. You should be able to 'feel' for it as a lump - carefully unravel it.
7) The wires correspond to L & R channels (Yellow & Green) and Earth (Brown)
8) Make your wiring harness so all the wires are connected to the right bits
9) plug it in and test it
10) You should be able to 'feed' it through to the glovebox via the a/c vent area without even removing the glovebox (but that could make it easier)

You DON'T need to remove the whole monitor at all. I wouldn't bother trying either! It is harder than it looks and you don't want to break it.

I've attached pictures of the process, parts, and finished product!

Hope this helps,

Paul Martin
Australia
(yet to put capacitors into the circuit - and reluctant to do so as it is all back together and working well... :eeps: )

nitram_luap 11-02-2004 12:26 AM

4 Attachment(s)
The rest!

You can see the P1 & P6 in the top right corner of the screen to signify the 'input gain' (P6 is louder).

This is done by pressing the numbered buttons beneath the MODE button.

Paul

dkl 11-02-2004 08:35 AM

Quote:

Originally Posted by nitram_luap
Thanks for the info.

As blocking caps what are they protecting, the stereo or the device plugged into it?

I've just bought some 0.22F capacitors from my local electronics shop (they were 20c each) and they are pretty tiny. I'll post pictures of them (and of the BMW end of the plug) in another post.

Paul Martin

Depending on how the amps (input stage of your stereo, output stage of your device...ie IPOD) are designed, there may be a DC voltage level on the signal to bias the amplifier properly so a signal can make it's full swing without clipping. For example, if there is only one positive power supply for the amplifier, it will need to bias at half the supply level so that your signal can swing both ways without clipping at ground or the ceiling of the power supply. With such a DC bias, you will need a DC blocking cap to remove it so that it won't interfere with the bias of the next amp stage. Of course, if there are two power supplies (positive and negative), then biasing is not necessary and thus no DC caps are required. But in most case, you would always want to have some sort of DC blocking cap just to be safe of any DC shifts.

dkl 11-02-2004 08:50 AM

Quote:

Originally Posted by nitram_luap
OK... Here are the 'parts'

These were all found at my local electronics store (Dick Smith's)

- Stereo Audio Cable (1 metre) (I found a nice round black cable)
- 3.5mm stereo female socket (x1)
- 3 pin plug (see pictures) (x1)
- Resistor 300kOhm (x1)
- Capacitors (I've bought 0.22F ones - yet to be tested) x2

You'll also need some heat shrink & a good soldering iron. The actual assembly is pretty clear looking at the diagrams on the PDF file.

The 3 pin plug fits PERFECTLY into the BMW harness and due to the plastic 'guide' it will only plug in one way. I'm not sure what it is exactly but I found it in the electronics parts section...

Steps:

1) Remove passenger trim gently (an old credit card is excellent to gently pry out the friction pins - there are 4 of them on this trim)
2) Remove the Trim from above the monitor (should be one remaining friction pin close to steering wheel). This trim 'shares' a friction pin with the passenger trim. There is also a clip (just pull out) above the centre of the screen on this trim piece.
3) Unscrew the 2 screws from the top of the screen which also hold the a/c vents.
4) Pull out the a/c vents (they just go click, click like a ratchit - they push in the same way)
5) You should be able to see the wiring harness
6) The 'female' plug for the AUX input is hidden, wrapped up in that cable fabric. You should be able to 'feel' for it as a lump - carefully unravel it.
7) The wires correspond to L & R channels (Yellow & Green) and Earth (Brown)
8) Make your wiring harness so all the wires are connected to the right bits
9) plug it in and test it
10) You should be able to 'feed' it through to the glovebox via the a/c vent area without even removing the glovebox (but that could make it easier)

You DON'T need to remove the whole monitor at all. I wouldn't bother trying either! It is harder than it looks and you don't want to break it.

I've attached pictures of the process, parts, and finished product!

Hope this helps,

Paul Martin
Australia
(yet to put capacitors into the circuit - and reluctant to do so as it is all back together and working well... :eeps: )

Looked like you did a great job at installing things and the reverse engineering!

Staring at your picture shows that the capacitors that you bought are only 0.22uF...which is 100 times smaller than my recommended 22uF. This should still work fine as a DC blocking caps, but you're also blocking signals lower than 450Hz (assuming you have a 10K input impedance). So your bass response won't be as good. Also, when you're getting the larger capacitors, try to find some non-polarized ones. Polarized capacitors are a pain to deal with especially if you don't know which DC bias is larger (your stereo or your input device). But there are ways of making polarized capacitors, non-polarized...you'll just need more parts for that.

nitram_luap 11-02-2004 02:56 PM

Quote:

Originally Posted by dkl
Looked like you did a great job at installing things and the reverse engineering!

Staring at your picture shows that the capacitors that you bought are only 0.22uF...which is 100 times smaller than my recommended 22uF. This should still work fine as a DC blocking caps, but you're also blocking signals lower than 450Hz (assuming you have a 10K input impedance). So your bass response won't be as good. Also, when you're getting the larger capacitors, try to find some non-polarized ones. Polarized capacitors are a pain to deal with especially if you don't know which DC bias is larger (your stereo or your input device). But there are ways of making polarized capacitors, non-polarized...you'll just need more parts for that.

Thanks dkl for your electrical engineering wisdom. I find all this fascinating, albeit a little over my head, but I'm slowly piecing it together. It is a little outside of my area of expertise - so I don't get the chance to fiddle with electronics often, but I like to tinker with my soldering iron. :)

I wondered why they were so small given that they had 0.22F on the drawer they were in! I'll definitely buy the 0.22uF ones today... and I'll check to see if they are non-polarised caps too!

Thanks for the help!

Paul Martin
PS: and to anyone out there who is going to make this - buy the 0.22uF capacitors and put them in the right spot.

dkl 11-02-2004 04:37 PM

You are very much welcome. This is the kind of ingenuity I would like to see from more people.

Paul, I think you want the larger 22uF (no zero or period in front). But if you want to stick with your original values of 0.22uF, then you already got the right part. From the pictures you've shown, they are indeed 0.22uF - no need to get new 0.22uF caps unless you want to use my suggestion of the larger values (22uF).

nitram_luap 11-03-2004 03:16 PM

Quote:

Originally Posted by dkl
You are very much welcome. This is the kind of ingenuity I would like to see from more people.

Paul, I think you want the larger 22uF (no zero or period in front). But if you want to stick with your original values of 0.22uF, then you already got the right part. From the pictures you've shown, they are indeed 0.22uF - no need to get new 0.22uF caps unless you want to use my suggestion of the larger values (22uF).

dkl,

I did a little reading around the topic and came up with this formula for the cutoff frequency.

f = 1/(2*pi*R*C)

f - Hz, R - Ohm, C - Farads

If R=100kOhm (apparently typical impedence for AUX audio inputs)
and C=0.22uF

..then the cutoff frequency would be more like 72Hz would it not? If so, that's not really a major problem - I would have been more worried about 450Hz.

Am I right in this thinking?

I'm going to put the capacitors into the circuit this weekend - I'll report back with my 'findings'.

Paul Martin
Australia

dkl 11-03-2004 09:13 PM

Yes...you are absolutely right...my bad on the number crunching...it's actually 450 rad/s, which equates to 72Hz. I was off by a factor of 2pi.

CWolfey 11-04-2004 04:31 AM

Nice Work nitram_luap !

nitram_luap 11-05-2004 03:45 AM

Thanks!

Well... I fixed the cable that I'd created earlier and added the capacitors (0.22uF).

It works extremely well and the sound quality is perfect - deep bass sounds don't appear to be clipped either. :bigpimp:

Not bad for a few bucks!

Thanks for the support and feedback. If anyone wants any help creating this AUX in wiring harness for cars equipped with Nav, let me know - I'll be glad to help (nitram_luap@hotmail.com)

I'm currently running my MP3 player through my stereo now using the AUX input and it's all hidden away in the glovebox!

:thumbup:

Paul Martin
Australia

ChadS 11-07-2004 11:48 AM

I guess if you are good with this stuff then it makes sense, but this seems like a lot of work for a part I was able to get from my dealer for $25. :dunno: How much are they selling the aux input cable for in Australia?

nitram_luap 11-07-2004 01:06 PM

Quote:

Originally Posted by ChadS
I guess if you are good with this stuff then it makes sense, but this seems like a lot of work for a part I was able to get from my dealer for $25. :dunno: How much are they selling the aux input cable for in Australia?

A couple of reasons I made my own:

- The list price for this is about $50 in the USA (this is based on online BMW parts sites) so I can safely double that for here (ie. about $100 AUD)...
- It can't be obtained easily in Australia, nor can they give me a price on it. All they say is that the part number is correct... :confused:
- It wasn't too difficult or time consuming and I enjoyed the challenge
- The fact that BMW charge even $25 USD for a part which would cost less than $2 is insulting. It should be a standard feature given the simplicity.

Paul


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