Car radio with external bluetooth module only mono

Thread Starter


Joined Jan 28, 2020
I have a 6006E CD RDS EON car radio and I build Bluetooth function into it. There are two 0R resistors in the wires from the radio module to the mixer module (it mixes the signal from the radio receiver and CD player and does a lot of stuff, which I don't know about). I removed these resistors and soldered a switch there (as you can see in the attachment).
When I use it in radio mode (as you can see in the picture) everything works, but when I turn the switch, the radio turns into mono mode (there is a pictogram on the LCD screen).
I don't understand why the radio 'thinks' the stereo radio signal changed to mono, if I only changed the sound signal (changed to an another stereo signal from BT). Do you have any idea how could I force my radio to stay in stereo mode when the sound signal changes?
Thank you,