Introduction: Add AUX Input & Speakers to Your Car's Radio

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About: I am a University of Edinburgh electronics engineering student.

I bet you have always wanted to listen to your favorite tunes in the car! Well at least I do.

My idea came up when I was browsing my car's player settings menu. I just noticed an AUX label so I taught that the radio may well have an AUX input.

All modern cars have this option and in most cases it is as a standart feature. It is just a jack into which you plug a cable and an mp3 player or a phone and play music. I made this instructable for all those that may not have paid for this feature when buying their car or or want to explore whether they can connect an audio device to the car's radio and play music.

I have also updated the audio system of the car by adding some extra speakers and plugging them into unused radio outputs.

Step 1: Investigate!

1. Figure out how to take the radio out. You can find info on the i-net or try yourself.

Make sure you use the right size of screwdrivers if you need to use them. When removing plastic parts - use plastic tools! You may find usefull to use plastic cards (like credit cards or something similar that you do not need).

2. Try finding some info about your radio on the i-net. I found this page http://www.tehnomagazin.com/Auto-radio-car-connector/GRUNDIG-Car-Radio-Wiring-Connector.htm There are some common types of connectors, but still radios differ by manufacturer and their connections are non-unique.

My connector looks like that on the 4th picture but without the D connector.

Step 2: Connect the AUX Channels

C-3 is what I am interested in. If you search the web you can find cables that are ready to be plugged there and will have an audio jack on the other side. 

I decided to do my own cable and put three crimps on a shielded cable. You can see the connections: pin 18 is the ground and pins 19 and 20 are the L and R channels.

Just plug the crimps and make sure they are not loose and won't fall out accidently.

Step 3: Enjoy for a While (still More to Go)

On the other side of the cable you can put a standard 3.5mm audio jack.

I decided to put a male jack as I wanted it to be mounted on the plastic and have no hanging cables around. 

The last pictures show the outside part of the jack where I can plug any standard 3.5mm audio cable.

Now you can enjoy your music coming out from the car's speakers!

Step 4: Add Connections for the New Speakers

I went on and explored the connectors on the back of the radio.

The car had speakers only at the front doors and it turned out that there are outputs for two more speakers that were free. 

The connections are marked with red - these are L and R Rear speakers. I was almost sure that these are powered, but just not used and so I decided to test that. As the radio is expensive and I did not want to see the majic smoke coming out of it I plugged into these free connectors a small 5W speaker which proved that there is sound coming out.

The next step was to figure out how to make four new connections. For best quality use standard radio cables. I found a cable like the one on the third picture. It it easy to take out two cables with the metal crimps.

You can see how I inserted the new crimped cables and now they look like the stock ones.

Step 5: Run Cables to the New Speakers

It is a pain to run the additional cables and make them unnoticeable.

I started from the front. It is important to tighten the cables all the way to the speakers so I used some cable ties. The type of cables I used is two-core cables with multiple wires (like the ones on the connector).

1 - Cables go uder the steering column. I tightened the cables to the air vents.
2 - On the left side from the driver's seat under the plastic pieces.
3 -  Cables run to the back under the plastic pieces.
4 - One of the cables continues to the right side of the vehicle again under the plastic parts.

Step 6: Mount the Speakers and Enjoy the Result

I don't want to look like advertising Sony - just bought 13cm speakers that would fit in the original mountings. There were empty places for the speakers to be mounted.

You can see how I bended the long mounting brackets so the outter diameter of the speakers was 13 cm and not more. Speakers fit in the cone-like shape of the mountings and lastly I have put some silicone sealant to stop them from falling down. 

There is the final result on the last pictures. Speakers are hidden inside like stock ones and they sound amazing! It was useless to put a tweeter in the separate hole as the speakers are three-way.


I am waiting for your suggestions and comments.