Hi everyone. I have decided to make a modification to my car radio because it does not have MP3 or bluetooth, only radio and CD. The modification in question consists of directly connecting a bluetooth module directly to the input of the amplifier chip in such a way that it directly injects the audio signal. In the tutorial I have seen it seemed simple because the amplifier chip pins were marked with "channel R", "channel L" and "GND". But when disassembling my car radio I have found that the amplifier has no legend on the pins, so I do not know where to weld the bluetooth module cables. My question is: Is there any way to know what is the input of the right channel, the left and the mass of the amplifier chip if it has nothing written? I could not see the serial number of the chip in question because I would have to desolder it and extract it completely, which would complicate the operation quite a bit. Attached photo of what I think is the amplifier behind: And photos of the interior: IMG_20191123_195518_290.jpg [2.08MB] IMG_20191123_195618_769.jpg [2.12mb]