# BMW - HOW TO: Build your own AUX in for Business CD (- NAV + DSP)



## audiogodz1

I needed a custom cord 12 feet or so to run from the top of my X to the radio and the only way was to build it. In the process of doing so, I documented my work.

This was done on a 2003 Business CD with DSP, no nav or changer was present. It will work for 2003 to 2006 for CERTAIN. I do not know about other years.

Total build cost $12. (I already had the $10 ipod charger from Marshalls)

Start with a few goodies from your local electronics store.





































Would be nice if Radio Shack sold 300K resistors, but they do not so let's make one. This resistor lays across the R+L positive and tells the head unit to go into AUX mode. Just laying the 300k ohm resistor across pins 3 and 4 of the area where the ipod in signal goes will give you the aux selection on the radio (otherwise you don't get the option).










...and let's make it nice and safe.










We're going to let the pics do the talking for a bit.




























Here the resistor (300K we made) goes across the R+L positive. The capacitors are on the ipod side before the resistor, as the resistor and head unit must see each other first to go into AUX mode.


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## audiogodz1

Just tape it all up and put it to the side for now since you've built the plug circuit. Since I am building into the overhead console I am going to do the writeup as such. Plug your iPod jumper cable into the new AUX plug and run it through to the other side.










Now pick yourself an iPod charger cable up and dissect it for it's guts so your iPod will charge when you are driving.










You'll use the green/red from the homelink plug for power since it turns on with the key and turns off when not in use. Ground to the sunroof motor mounting screws.










Run your AUX wire in through the roof and get it plugged in properly to the iPod and set up. 

Bolt it all back up after you have made the connections for power and AUX to the ipod.










Set the iPod in to it's new space and connect it up.










Turn the key on and see if your iPod is charging and has the little lightning bolt in the battery symbol.










Pop the cover off your pillar and unscrew the screw to allow you to remove the pillar cover so you can run the wire down.



















Stay away from the pillar airbag, run the wire along with the drain tube.










Then drop the lower pan from under the driver dash (couple screws and a few twist locks, no biggie) and run the wire over to the radio and feed it through.


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## audiogodz1

IF you look in the back of the plug where you are supposed to plug in (bottom right) it will be numbered. Pins 3 & 4 are R+L positive and pin 10 is common ground. 










The pins are very common so picking up a few female pins to put on the end of your wire is easy enough, then just plug the wires in to the pins.

If you did it right, you will now have the AUX option when going through the sources. Turn the ipod on and ENJOY!!!!!  : )











..........and the video!


YouTube - E53 ipod aux mod from scratch

^ Proof of concept 




*****TROUBLESHOOTING*****

**Note if you experience a rumbling or humming sound when switching artists you need a ground loop isolator. Hard drive iPods are more susceptible than flash memory iPods.*

Get any average isolator and open it, change the rca's to straight wires. Tie the grounds together on each side to make it common ground. Put it inline between the 300K resistor and the iPod. Make sure the resistor stays in front of it all and the radio see's it first. Remove the .022 green caps completely from the AUX plug you made. You obviously can do this right from the beginning without doing the capacitors, but isolators are $20 or so and you might not need one.


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## tibug

Man, you know what you're doing! This would be a big help..but I don't have a BMW...I might just have to buy a BMW and do this. :laugh:


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## nismos14

I don't understand the title of this, build your own aux in for *Business CD (-NAV +DSP)*?

Great worK!!


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## bobdole369

I guess Business CD is the type of radio. In any case - Great clean work there!


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## el_chupo_

nismos14 said:


> I don't understand the title of this, build your own aux in for *Business CD (-NAV +DSP)*?
> 
> Great worK!!


For a BMW with Business CD option, without Navigation, with the BMW DSP system installed(or at least active).

Kind of need to be familiar with BMW audio to get all the stuff.


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## CHH777

nismos14 said:


> I don't understand the title of this, build your own aux in for *Business CD (-NAV +DSP)*?
> 
> Great worK!!


Look at the upper left corner of the head unit.


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## nismos14

Lawl @ me thx


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## kenikh

DAYUM! You muff huckazz iz KRAZEE good! 

I am consistently amazed by the ingenuity I see on this forum. Kudos.


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## Chuck

I'm curious - how is this better than simply paying BMW the $30 for the Aux-In kit and just plugging it in to the back of the radio? Thats what I used on my M3, and I didn't have to do any cutting, soldering, or hacking up iPod stuff. It took me less than 30 minutes. I believe its BMW p/n 82 11 0 149 389.


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## audiogodz1

^It's $50. You're getting a quote for the cable ONLY which doesn't fit the non Nav 2003 W/DSP and I clearly stated in the first line I need 12 feet of cable.



nismos14 said:


> I don't understand the title of this, build your own aux in for *Business CD (-NAV +DSP)*?
> 
> Great worK!!





el_chupo_ said:


> For a BMW with Business CD option, *without Navigation, with the BMW DSP* system installed(or at least active).
> 
> Kind of need to be familiar with BMW audio to get all the stuff.


 ^ This guy. ^


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## danno14

nicely done! 

Debating between a Business, Traffic Pro, and (perhaps) MX406. Aesthetics matters!


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## UNFORGIVEN

wow that's great.

any links or tips on how to do this with other vehicles. honda/toyota/etc.


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## azluda87

good job, you should post it on other bmw sites, or i can link to a couple if its cool with you


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## Mless5

Dope! Thanks so much for posting this. Will be doing it tomorrow.


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## EIP11

Would this work on a 2002 X5? It has the same options as yours except mine has the disc changer. Is there maybe additional steps to doing this with this year? Please let me know, I've been trying to get an aux input for a very long time but just haven't been able to figure it out.

Thanks,
Elvis


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