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How to install an aftermarket radio without a wiring harness

Old 03-22-2010, 02:11 PM
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Default How to install an aftermarket radio without a wiring harness

Hey everyone, So I just finished figuring out how to get my aftermarket radio working in my non-bose Symphony. I figured I would make a small write up in case anyone else ever needed the info.

The problem with this audio set up is that the two rear speakers in the car are run off a small amplifier that is attached to the rear driver side speaker. What this means is that the rear speakers cannot simply be attached to a new radio. You need to attach the 2 rear speakers to the pre-amp outputs on your aftermarket radio (RCAs).

Before I start I would like to say that it would have been much easier to simply buy this wiring harness. But, if you are so inclined, you can do it the hard way like me


Step 1:
The first step is to remove the stock radio, this is done by putting 4 pins into the 4 slots of the radio and pulling it out. Here is a picture of the 4 holes:

radio.jpg?t=1269215909

As far as what to put in the slots, you can easily make your own tools to remove the radio. I simply took a thin piece of sheet metal and cut out the appropriate shape:



Once you have the 4 tools just stick them in the 4 holes and pull out the radio.



Step 2: Once the radio is out all you have to do is connect all the wires. There are 4 plugs in the back of the stock radio, we will need 3 of them.

Here is a diagram with all the wires you will need:



1=Ground
2= 12v Constant
3= Illumination
4= 12v Switched
5= Front left speaker (-)
6= Front left speaker (+)
7= Front right speaker (-)
8= Front right speaker (+)
9= To rear right speaker via amp (2v)
10= To rear left speaker via amp (2v)
11= Remote turn on lead for amp

1-8 is fairly self explanatory, it's the same as any other radio install. Simply solder those wires to the corresponding wires on your new radio. 9-11 is what gave me problems.

Step 3: To power the rear speakers you need to send a pre-amp current to the little amp and you need to tell the little amp to turn on. To get it on just connect 11 to your remote turn on from your new radio (usually blue).

Now to send the current to the amp we need to make some RCAs with 9 and 10 and then connect those RCAs to the pre-amp outputs on your new radio. Buy some RCA plugs at radio shack and make something like this:
DSC01387.jpg?t=1269239178

The middle prong is the positive and the outer shield is the negative.

Red RCA connect wire 9 to the middle prong and connect the outer shield to the ground wire 1.
Black or White RCA connect wire 10 to the middle prong and the outer shield to ground wire 1.

Once the RCAs are made and connected to the back of the radio you can plug everything back in and slide the radio into place.



Step 4:
If you want to listen to radio you will need to buy this adaptor to be able to plug in the stock antenna. I'm sure there is a way around this and if I can find a way to do this without buying an antenna adaptor I will update this.

Step 5:
Now that all the wires are hooked up you simply have to put the radio into place. The problem is that most affordable aftermarket radios are single DIN radios (1 slot) and the whole in our dash is a double DIN (2 slots). The most simple solution is to buy this kit and install the radio in the dash as per their instructions. If you don't feel like dropping the 30$ you could always make something custom. I am currently working on mine and I will update this once it's done.

Until then my radio is just kind of sitting there:

IMG_0041.jpg?t=1269295776

You can use the bottom bendy things from your radio to hold it in place temporarily.




I hope this helped somebody, if you have any questions or comments feel free to reply.
Old 03-24-2010, 08:12 AM
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Looks good thanks for the details!
Old 03-24-2010, 08:41 AM
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thanks for the write up. also, while changing the radio, is a good time to replace the faulty turn signal relay(hazard button). i know i don't want to pull the trim pieces off any more than i need to. those clips break off too easy
Old 03-07-2011, 07:28 AM
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Hello, First, thanks for this post, it's wonderful! My rear speaker work.

I have an audi a4 2000 1.8T.
I change my radio-car and i use this post for solve no rear sound.
I connect two rca and positive wire (blue in radiocar) to din of car. IT'S WORK!!!

But i have a small problem:

ON rear i have 4 speaker, only two (on rear panel) work. Two on rear door don't work. With my original radio, all work.

I test to put + rca to connector iso on "COM" pin but it's for rear panel speaker in mono entry.
In my connector din of my audi, i don't have pinout RF and LF.

Where is pinout for door rea speaker please?

And i found my signal antenna it's poor, i see is possible my car have power antenna supply, where is pin please?


Thanks in advance for help.
Old 09-12-2011, 06:48 PM
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DUDE I ****ING LOVE YOU!! LOL thanks so much on my radio that blue wire was labeled antenna control signal
Old 09-13-2011, 05:02 AM
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You can get a complete face plate, harness and antenna amp for less than $20.If you have Bose you buy the second loom with the (line-out) RCA connectors.

It's no more than an hour to remove the radio and reinstall an aftermarket one, with the benefit that you can convert it back to stock very quickly.

Why anyone would go to this kind of trouble is beyond me.
Old 01-16-2013, 09:22 PM
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Default Connector on speakers not there

Hi, this thread is very helpful. My problem is whomever installed my aftermarket HU pulled the connector off all the wires that go to the speakers, etc, so I can't look at this diagram and connect A to B. If anyone could look at their connector and tell me which color wire comes out the back and goes to the speakers and amps that would be fantastic! I can't find any source online that has this info.

2006 Audi A3 with Bose system.
Old 07-31-2013, 09:56 AM
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Default trouble getting power to my new unit a4 b5

hi every one i hope were all well today. i am having a job working out how to get power to my new head unit the ones shown here are i assume the correct ones and i have followed the instructions but there is no power going to it there is power in the lines so to speak and the old one (standard one)was working b4 i removed it but the new dam stereo isn't lighting up at all i've checked the fuse's and none are blown or faulty so i'm now at a loss as to what to do next. i hope someone can help.... thanks for your time
Old 07-31-2013, 11:06 AM
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hi every one i hope were all well today. i am having a job working out how to get power to my new head unit the ones shown here are i assume the correct ones and i have followed the instructions but there is no power going to it there is power in the lines so to speak and the old one (standard one)was working b4 i removed it but the new dam stereo isn't lighting up at all i've checked the fuse's and none are blown or faulty so i'm now at a loss as to what to do next. i hope someone can help.... thanks for your time
Old 09-14-2013, 02:22 AM
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Default Wiring diagram

G'day, Found this online, hope it helps in some way even if not for your particular model
Cheers Garfield13
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