Need Help - OEM car stereo Blutooth mod NOISE/STATIC

Thread Starter


Joined Nov 6, 2022
Hey guys, new to the site and am hoping there is someone here willing to help point me in the right direction.

I'm currently building a car and being the tinkerer that loves all things electronic but am by no means anything close to having a degree in anything alike as im just a dirty concretor

I have decided to try modifying my cars factory headunit to have blutooth As I want it to all look original.

Stereo - Eurovox MCC-6329
Blutooth Module - cheap ebay 12v BT07 Module
Pre-amp chip - LA3161

So far I have managed to wire in a blutooth module from ebay with

.12v+ to the casset players motor possitive wire
.-ground to stereos casing
.left/right channel & ground i connected to the 3 corresponding outputs on the preamp ic chip I think it is

And am currently getting alot of unwanted noisy interference and the sound is not that loud.
ALSO without the L+R channel wires connected you can still hear what ever playing somehow but only slightly with the same interference.

How can I distinguish between
1. ground Loop
2. Connected to the wrong part of the pcb
3. Is it my Regulated DC power suply i have been using to power my headunit on a test bench?
4. Any other reason for the noise?

I don't know where to start. I have posted wiring diagrams pics etc if anyone can help would be much appreciated. Thankyou

The stereo manual I have is too large to upload.20221106_223310.jpg20221106_223319.jpg20221106_223333.jpg20221106_223302.jpgScreenshot_20221106-221827_Drive.jpgScreenshot_20221106-221803_Drive.jpgScreenshot_20221106-221539_Drive.jpgScreenshot_20221106-220154_Drive.jpgScreenshot_20221106-220211_Drive.jpg