Add Bluetooth to Your Old Car Stereo

Hi everyone! This is my first time sharing some of this projects, I hope you can get at least some ideas to bring back to life your old car stereo.

My native lenguaje is not English, so, I'm sorry if my orthography or my grammar is not right.

Supplies

You will need:

Screwdriver (Philips)

Iron welder

(Recommended) thermal paste

(Highly recommended) A multi-meter.

A cheap wireless bluetooth headphones (I got this ones for about $5 USD, the cable were already damaged)

of course, your old Stereo.

Step 1: First Step

Make sure your bluetooth and your stereo Already works!

You must disassembly your Stereo, just, put off every screw you can see. and then, pull of the cover.

This Step may be all way different which every Stereo, so, you must find the way to disassembly until you get to the PCB

Step 2: Find the Components We Will Need on the PCB

We must find util components or layers on the PCB.

So what do we are looking for?

We must find, a layer on the PCB that makes reference to the audio channels, lije R+, R-, L+, L-. or maybe we can find it as R,L and GND.

Usually this labels will be on the back of the PCB, the usually "Green" layer.

In my stereo, I find two possibles components, the Radio Receiver, and the Amp itself.

We identify the amp, because it is a big chip, with a cooler,and maybe with thermal paste.

This Amp, must have a serial number, that we can use to google it, and download it datasheet. the datasheet is a paper with extremely Technic and util info for example, it says what is every pin for, how it works, and more.

Here you can use a multi meter, to find which line have continuity to the AMP and solder directly to the AMP. (Is just a suggestion , if you want to make it in the easiest way, you should be going for the already labeled chanel audio.)

Step 3: Soldering

It's just no more to say, I hope you know about how to solder with the Iron.

All you gonna need to do, is solder the R or R+ ping of the Stereo PCB directly to your bluetooth device, or, do it as I did, I took some Ethernet cable, got a twisted pair from it, and just soldered the R,L and GND to get the cable outside the Stereo, just to make sure that works properly.

Is you label is R+, R- and L+, L-, you can use just 3 wires, one for the R+, one for the L+, and you can join the R- and the L- in the same cable.

Your bluetooth headphones must have the same layer on it PCB, saying if is R+, R- L+ and L-, you just need to solder each one with the same label.

Step 4: Reassembly

Well, you just need to find a hole where your wires (if you soldered larger ones as I did) go out.

Take your time, to clean the AMP, and add some new Thermal Paste to make a better heat transfer.

Connect your stereo to your car, turn on your bluetooth headphones, and test it with your phone.

To listen your music you must consider this:

If you connected the bluetooth to the Radio receiver (as I did) you must turn on the Stereo and select the Radio mode, so you will listen your phone.

If you connected the bluetooth to the CD output, so you must select the CD mode, if that doesn't work, you must insert a blank CD to make it sound.

If you soldered the bluetooth directly to the Input RCA connection, you must select the LINE mode on your Stereo.

If you soldered directly to the amp, well, you don't need to do anything, the stereo should be working already.

Step 5: Off Topic: Some Troubleshooting

If you have very bad luck, as I had, you can check this, maybe can help you.

My stereo screen doesn't worked anymore, and I can't change to radio to listen the music.

So, the PCB of the screen, had 14 pins, where the number 1 pin, doesn't had contact with the cable, so I solder a little cable from the input, to the conector, My screen still no working, but now I can change to Radio mode and listen to my music.