[zoti]

So you have a nice iPod / iPhone but you cannot connect it to your factory stereo system because it has no aux input.

I have the Harman Kardon system installed in my car with the 10 speakers and a CD changer in the back. I wanted to keep the CD changer so that ruled out most of the adapter boxes that replace the CD changer with a connection for an iPod/iPhone.

Here's what I have done. First, I read the following thread: http://www.r3vlimited.com/board/showthread.php?t=118781

The guy did a good job. I thought about the same idea but actually didn't know how simple it is going to be.

You will need:

- A BMW radio key (you can use a 2mm Alan key instead).
- Your radio CODE! Very important. Do not take the radio out without having the code.
- a 3.5mm stereo plug with a cable. A few $ at Radio Shack. I just used an old one I had lying around.
- A VOM (voltmeter) to check continuity.
- A soldering iron with a small tip and some solder.
- A cutter to cut the wire.
- Some tape.

First, you remove the radio from your car using the radio key. Then unplug the plugs at the back. The main plug is a bit tricky but follow the illustration on the top of it and it will come out.



Next, Remove the 2 screws holding the top cover. If you look at the back of the radio they will be the top left and top right ones. They pry the top cover off with a flathead screwdriver.

Inside the radio you will see the tape mechanism. It is held in place by 4 screws. Remove them and pull the tape mechanism out. It is sitting on the main board with a plug much like the one in the back of a hard drive but with only one row of pins.

On the back of the tape mechanism there is a PCB with electronic on it. At the top left of it there are connectors coming from the tape reading head. Look at the picture below.



Before you solder anything pass one side of the cable through the top cover like in the picture below. This is after the radio was already assembled together but you get the idea. Pass it towards the rear of the cover. Leave enough cable (I left about 2.5 feet) so it can reach around to your iPod.

Take your stereo cable and solder the end of it to the board as in the picture above. The left most soldering point is GROUND. The second one is RIGHT CHANNEL and the 3rd is LEFT CHANNEL. Referenced from here:

TRS connector - Wikipedia, the free encyclopedia

TRS connector - Wikipedia, the free encyclopedia

Test to see that everything is connected correctly and that you did not create any shorts.

Tape the cable to the back of the tape mechanism so it does not get pulled and take the soldering points with it.

Now, a little trick. If you look at the picture below you will see a small, black micro switch in the center of it. It has 4 legs and it tells the radio that you have inserted a tape in it. When you put the tape in a mechanism of levers will release this switch and will operate the tape loading arms. We need to disable the switch and we do this by removing the spring and then pushing the arm that is holding the spring down.



Tape the spring and the arm to the top of the tape mechanism so they don't move. I left the spring in there in case I ever want to put it back together.



Tape used.



Put everything back together. Put the tape mechanism back in it's place and the screws that hold it. Route the cable inside the radio so it is not disturbing the top cover.

Back to the car.

Put your finger through the hole in the top of the sunglasses tray and push the climate control unit out. You DO-NOT need to disconnect it.





Route the cable like in the picture. In through the right back side area of the radio location and down through the hole in the sunglasses tray.



Install the radio back. First plug the cables. Turn the key on and turn the radio on. It will ask for the code (I hope you have it) and then you will hear the tape mechanism work loading the nonexistent tape. This is because we have set the micro switch to TAPE IN position. It will only happen once.

Connect an ipod and press the TAPE/CD button. It will show TAPE A and you will hear your iPod. Press the button again and it will operate your CD changer.

Push the radio back in and use the radio key to turn the screws. Put the climate control unit back in.

If you want to have the option to charge the iPod as well you can buy this: http://www.griffintechnology.com/products/autopilot

You plug your AUX input to the AutoPilot and the iPod to the AutoPilot iPod connector. This way you only have one plug to connect your iPod to when you put it in your car and it will charge it and play the music.

Picture of final installation. The iPhone cradle is also made by Griffin.

[zottyzot]

Excellent write up!! I'll be doing this soon. Maybe you could wire a female jack and mount it under the dash or in the glovebox...

[zoti]

you can have whatever you want at the end of the cable and route it anywhere. There is a radio on sale on eBay which has an auxiliary input installed to the front of it.

Btw, the griffin adapter is creating engine buzz but it does not do it on my Honda where I gave a similar setup. How do I get rid of the noise? If I plug the aux directly to the iPhone headphone output there is no noise so I know it's the power adapter.

[BleedsBlue]

Nice writeup.

What's with the 'zot' theme

[zoti]

It's "zoti". An old highschool joke.

[zoti]

A small update.

I have added a ground loop insolator from Radio Shack and I had to do a lot of connections to it in the line from the radio to the iPhone. It removed the engine buzz but also made the music sound terrible.

I'm going to putt the radio out and install AUX outputs in the back of it. Then test it with the ground loop insolator to see how the sound quality is. If it is still bad then I guess I will have to hook the iPhone via the earphone output and charge it seperatly when I don't listen to music.

I really want to hook the iPhone via the plug at the bottom of it. The shoud quality is better that way.

[KWorker17]

This is awesome! I've always wondered on how to do this?! Good write up

[zottyzot]

Originally Posted by zoti

A small update....It removed the engine buzz but also made the music sound terrible...

No offense, but that reads pretty funny.
The "zot" in my case relates to my last name.

[zottyzot]

Could this be of any use? http://pinouts.ru/Devices/ipod_pinout.shtml

[zoti]

I have made some changes. I pulled the radio out and installed AUX plugs on the back of it.



I then connected just one cable with a 3.5mm stereo jack at the end of it. It wokrs much better than the first cable (which was some junk I found at home). No engine buzz when connected to the iPhone directly and very minimal buzz when connected through the PowerJolt.

I play techno in my car anyway so the minimal buzz actually helps :P.