Add an auxiliary (MP3/Ipod) input to your car's stock radio

So you've got this great little MP3 player or Ipod, but your old-school car only has a CD changer? Sure you can get an FM modulator, but they don't work so great and are notorious for poor sound quality. I decided to leverage the CD player in my car to add a CD-quality auxiliary input for my MP3 player.

What you need:

-- Stock car stereo with a CD changer input
-- Basic Soldering Skills
-- Soldering Iron & Solder
-- Hand held Volt/Multimeter (to find right wires)
-- Small gauge speaker wire (anything around 18-14 gauge will work)
-- 2 panel mount 1/8" stereo phone jacks ($2.99 for 2 at Radio shack)
-- 1/8" stereo plug cable ($5.99 at Radio Shack)
-- Old pair of headphones (really just need the wire & 1/8" plug)

Essentially what you are doing is sending a pirated signal from the MP3 player onto the line that would normally be sending audio from the CD changer. In order to prevent a mixing of the audio from the changer & your new pirate Aux input, you have to play a special CD which contains tracks with perfect silence. It may sound complex, but is quite simple with some basic electronics/soldering skills.

Step 1 Remove your stock radio from the car

This is probably the biggest challenge in the whole project. If you do any work on cars, then your shop manual will help, but also there's tons of user forums dedicated to specific car models. Google around a bit and you should be able to find tips & help.

You may also try calling local car audio shops and ask them for tips on how to remove the radio from your specific make/model. Most are moderately friendly and will give you tips, just don't expect them to come do it for free or anything.

Comments

[messaround]

I looked through this whole thread and didn't see an answer to one of the very first questions posted: Can you somehow use the CD changer interface IF YOU DON'T HAVE A CD CHANGER. I have a radio/cassette deck in my 2004 Sprinter van. I don't like the fake cassette adapter solution or the fm transmitter solution. I might have to settle for one of those if I can't hack an auxilliar input of some kind. So how about it? Can I use my CD changer interface without a CD changer?

[Kirstareis]

If you have a casette player you are golden!!! Buy a tape with an audio jack at the end of it. Its about 10 dollars at walmart. It has the same audio quality as an aux I personally love it because its cheap. Although try not to shut the wire in your car door it tends to make it die. But thats ok cuz its just 10 bucks LOL. I unfortunately got a new car that doesnt have a tape player :( so now I have to find an alternative.

[31mimo]

The motor of the K7 player makes to much noise!Solder the 3 wires direct to the reader head of the K7 player!

[wmccutchan]

You don't need a CD changer to make it work. HOWEVER, your stereo does need the CD changer input. That's the key. If you don't have that output it won't work. His bullet points actually answer this question by the way:

*******************-- Stock car stereo with a CD changer input*************** (says nothing about having an actual CD changer in your car. You probably CAN'T set this up and have the CD changer still working to be completely honest.)
-- Basic Soldering Skills
-- Soldering Iron & Solder
-- Hand held Volt/Multimeter (to find right wires)
-- Small gauge speaker wire (anything around 18-14 gauge will work)
-- 2 panel mount 1/8" stereo phone jacks ($2.99 for 2 at Radio shack)
-- 1/8" stereo plug cable ($5.99 at Radio Shack)
-- Old pair of headphones (really just need the wire & 1/8" plug)

[aka_bigred]

This instructable isn't about replacing the CD changer, it's sending a pirate AUX signal to the radio. As far as I know, you MUST have a CD changer. At least in my car, it wouldn't work without the CD Changer registering with the head unit.  

Without the CD changer, most head units (ie stereo) I've seen won't even accept (or won't even look for) the signal produced by the changer lines. That's where the silent CD comes in - the head unit thinks the changer is sending the audio signal, when it's really being sent by the MP3 player pirate signal!

@wmccutchan - I originally came up with this because I wanted BOTH the CD changer AND MP3 input, and all the aftermarket interfaces I could find made you swap out the changer for an AUX input but I wanted to add to the stock functionality.

[inkyfinky]

PLEASE HELP :)
I hooked everything up perfectly...even used a multimeter to check my connections (and they were fine). With a silent CD playing, I plugged in my ipod and heard that crackle over the speakers (indicating the speakers are hooked up correctly). But then...the ipod stopped playing and just shut off. Has this happened to anyone else? Is the ipod getting a surge of power somehow? Can anyone please explain what is going on? Thank you so much!

[needexercise3]

Wonderful idea, wish I'd been brave enough to try this before! I'll be pulling out my car stereo and having at it.

[aka_bigred]

Yep, It's not too hard. If you can solder and are capable enough to remove your car's stereo, you should be able to do it fine. Good luck - you won't regret it after you hear the difference in quality between this and the crappy FM transmitters.!

[Lee Wilkerson]

The crappy FM transmitters of which you speak can be greatly improved by adding an antenna extension (3-5 feet). I applied this concept to my Belkin and now it only gets a little bit of noise when driving downtown among all the other commercial/industrial transmitters. You can then drape the wire across the top of the dash or tuck it behind trim on the car radio antenna side of the windshield.
Do ya think I should make an 'ible?

~/Lee

[jdogtotherescue]

we are familiar with your idea of putting an antenna on the transmitter but what we are trying to accomplish here is the elimination of the transmitter altogether. Transmitters aren't very good. They are good if you don't have your own car or you change cars a lot but if you only drive one car then an auxiliary input is the best solution.

[eguerra1]

Make an auxiliary jack out of the fm transmitter you can hide all the stuff neatly in center console or glove box

[aka_bigred]

As jdogtotherescue said, this instructable is about NOT using an FM transmitter as they provide notoriously bad sound quality. This hard-wired strategy gives you CD quality sound.

[parekris00]

Hello,

I have a silent CD, but when I play musicfrom my ipod, I hear only the first 3-4 seconds. Can anyone help me?

thanks in advance

[nil8rr]

Did you only burn a single track CD? The silent track is only 5 seconds long. If you don't fill the CD with as many silent tracks as will fit, then the CD will only play the silence for 5 seconds and turn off. This might be what's causing your issue.

[parekris00]

The CD is full with silence tracks. I tried also a silent track of 20 sec. But the problem is still there.
Don't know what to do ..

[joeyoung25]

This should be possible. You should only need to connect 3 wires I dont know why you would need 7. If you look at step 2 it shows the diagram of the changer output you should connect the ground pin to the ground on your radioshack jack and left to left and right to right. as far as getting the stereo tricked to thinking its connected to the changer so you can hear audio thats a whole different story and would be completely different between stereo manufacturers. I want to do this same thing to my Chevy Colorado but only with bluetooth. I dont know how possible this is but I dont feel like plugging in a cable to my phone everytime I get in. My phone is mounted in the GPS dock on the windshield so I plan on running a USB port inside of the head liner above the rearview mirror so I should have no wires showing at all but will be able to charge and hear the phone, music, GPS etc. If anyone else reads this and has any ideas of how to wire a bluetooth adapter to my stereo please let me know. It does have an option to have bluetooth handsfree but mine doesnt have it as far as I know.

[HoldOnTight]

I like how you hid it in the pocket, so the car can be returned to stock if desired! I ran across this because I want to do something like this only my stereo is double-din sized, so I'll try to put it on the edge of the double din frame.

[shperka]

Thanks for the tutorial! I have a Chrysler Voyager 1995 stereo with a jack to 6 CD Changer, but i do not have the changer. Is it possible to play music via the CD Changer jack without CD Changer? I mean, is there a way to transmit audio signal only with a wiring that will lie the stereo it is connected to cd changer?
Thank you!

[flythesky]

(removed by author or community request)

[flythesky]

I don't have a CD changer but do have an Acura CD head unit with plug identical to the one shown. I'm wondering if it might be possible to open up the unit and insert the mp3 player signal into the main CD player output and play the silent CD in the main unit while playing the mp3 player?

[xTyD23x]

I am doing this in a 2002 Nissan Maxima. How are the wires connected to the aux jack? I bought the one from the link to Radio Shack and don't really understand how to connect the wires properly. I found the terminals on my head unit where I will connect the wires, but from everything I have read elsewhere, I will need to connect 7 wires. I understand where to solder these 7 wires on the board, but what do I do with the other ends???

[tmw25]

Hi there.
I'm thinking about doing this to my 2002 maxima as well.

Where did you find the pinout diagram for the cd player?

Thanks

[xTyD23x]

Sorry, I wasn't able to get this working right. After I had soldered everything (very poorly) to the head unit, I thought I had it working. I put the disc in the CD player and attempted to play it but it wasn't working. I was pretty depressed and finally gave up and put everything back the way it was. I never found a diagram for the head unit, but I tried to make sense of the labels on the board. I can' t remember exactly what they said but they were labeled and you could figure out what they meant. Let me know if you are successful with this. I usually love messing around with stuff like this but I wasn't able to figure this one out.

[anyoldmouse]

If I understand this correctly, the idea of making a silent CD is so that the content of a CD and your iPod don't mix. Could you not just pause a normal CD and use the iPod?

[aka_bigred]

That may work. I wanted a dedicated disc to remind me I was in "MP3 mode" and not worry about accidentally un-pausing to end up with a mess of music playing all at once.

Whatever works for you.

[anku10]

Could this be used as a way to bypass a nonfunctional cd changer? The cd changer in my '03 Camry doesn't work anymore, and I didn't really want to buy a new deck. My entire music library is on various digital devices, so I don't need the CD changer anyway, but I would like to add the auxiliary jack. Can I complete this project with the nonfunctional cd changer?

[moiztankiwala]

My car stereo is a single audio CD player. Any suggestion on how I can attach the Aux input for my iPod?

[maso08]

So this is basically a 5 disc changer with mp3? If you still keep function of the changer, then that is so tight.

[aka_bigred]

Yes, that's exactly what it is.

[stangswang]

I just discovered one added benefit of doing this, over the use of the cassette adapter.  I realized that I wasn't getting any of the GSM cell phone chatter on incoming phone calls or text.  This is an improvement when using the MP3 player, but I haven't checked to see if it is better when listening to radio.  Can't see why it would be, but I also can't see why this would be better with the MP3.

[kris_sti]

Ok I really like your guide, It inspired me to try and do something simmilar, I just have a question before I do.

my car (07 Accord) has a built in cd changer, however on the back there is a cd-changer port, with more than 3 (gnd, lt, rt) pins, is there a way I can figure out which ones I need for audio.

my reasoning that this may work is that honda sells something called MusicLink all it does is hook up to the cd changer port and has an ipod jack, but it costs $230+, all theirs additionally supports is charging the ipod

[Lee Wilkerson]

Couldn't you just pause a regular music CD?

[stangswang]

if it wasn't answered, it depends.  My Ford CD player doesn't have a pause.

[Djox]

 Hi i am trying to get my ipod working with my factory HU in nissan micra 2005... i read this DIY, and trying smething but it did not work! i found the info about pinouts of my HU "link" and i think that i should use 18,19,20 pinouts on bloc C right? as mentioned above, any help?

[geekdude]

cant get to your link. so idk.
im guessing you wont be able to do the same cd changer trick we did with a newer car. newer cd changers tend to digitize the audio before sending it to the radio.
you might be able to find a input jack or wires for one though.

[stangswang]

My friend just introduced me and this is a great site. 

I have a question about this hack.  I had thought something like this would be great in my car.  Aux input for a little sweat and less than $10.  I have a wiring question though.  My stock ford stereo has a radio/cassette/control head unit, amplifier, and separate CD player.  I have the wiring diagrams and they indicate that there are 5 wires for audio signal: left + and -, right + and -, and ground.  An MP3 player has only left, right and ground. Does anyone know how to wire the two together?  Is this a balanced io between CD and head unit?

Also, and I will test this before executing, there is a "logic sense" line between CD and head.  I am thinking that I'd be able to avoid the silent CD and switch in a high or low signal (whichever is required) to activate the CD path.  Note again that I will test this for voltage levels and other potential control signals before executing.

Anyhow, thanks for any advice on the audio signal wiring.

[aka_bigred]

I don't know for sure, but I would think you connect both L&R '-'s together and connect that to the MP3 ground, then put the left and right wires to their respective + wires.  Here's how I'd wire, but you should test for your situation before blindly doing this:

MP3 Right = Radio R+
MP3 Left = Radio L+
MP3 Ground = Radio R- & Radio L-

That logic level part sounds like a good idea if it works for you.  If you can decipher & replicate the signals on your own, there's no need for the silent CD - which is just an ultra low tech hack to pirate the audio signal

[stangswang]

[stangswang]

or...I think I posted the diagram.

[stangswang]

Thanks ABR
I looked closer at the CD player side of the diagram and it indicates the '-' is an signal 'in'.  hmmmmm.  The radio side indicates the '-'.  First stop will be connecting to the left/right + and the ground.  I am certain I won't blow anything...i hope.  I posted the diagram.  someone else might appreciate it.