I soldered the AUX IN cable as in the diagram, added capacitors. In the diagram, pin 4 is GND. I insert a CD with a silent recording and unfortunately nothing comes from the smartphone. I will add that I am a complete amateur in these matters. The soldering went quite smoothly, no cables touching or soldering. I read threads somewhere that in a similar radio they cut off the beams from the CD stereo, but how to do it (link to the thread below) and then solder R and L. I also tried without capacitors.
automotive - DIY Aux In connection to car stereo JVC KD-G151 - Electrical Engineering Stack Exchange

MANUAL:
Service Manual - JVC KD-G162 - Car CD Tuner (opweb.de)

 

Use a bluetooth to FM adaptor. I find them for less than $10. No wires, no modification of radio.

 

I know, but I wanted to modify this radio.

 

It seems you‘d be much better off using the radio input with a DPDT switch or relay to select between radio and aux.

The amazingly janky idea of a “CD of silence” is like a joke.

 

I know, but I wanted to modify this radio.

What advantage do you see in that?

 

It seems you‘d be much better off using the radio input with a DPDT switch or relay to select between radio and aux.

The amazingly janky idea of a “CD of silence” is like a joke.

Could you simplify it for me how it will work. I have never heard of DPDT

 

Sth like in this video

 

Could you simplify it for me how it will work. I have never heard of DPDT

DPDT means double pole double throw. It is a classification for a switch or relay that has two independent mechanisms able to each switch one input to two outputs or two outputs to one input. As a result you can use it to select between the radios output as input to the pins of the IC in the E.VOLUME block.

A DPDT switch or relay, you can connect a two channel output to the P side
and switch between two inputs connected to the T side, or in your case,
connect two outputs to the T side and select one or the other
as the input to E.VOLUME connected to the P side.​

A relay is an electrically operated switch. By using a relay you reduce the number of wires you need to run remotely, and avoid using long wires for the low-level signals you are switching. You would put a SPST (single pole singe throw) switch somewhere convenient, if you have some unused switch positions on the dash that have blanks, you can either mount by drilling a hole in the blank, or if you want to be really slick, buy a switch for something that fit into that spot and use it. It would look like it was an OEM feature. You can use this same idea to mount a jack for the aux input.

You would want to use a small relay, like this one, that you could fit inside the radio to keep the audio connections as short as possible. The relay’s coil needs power. The best thing would be to grab some from the internal power supply connections so everything can be inside the case. I would find a way to mount a connector but if there was no space, then I would use a pigtail and have it hanging out of the case in such a way the case could still be closed. (I would do the same for the new aux input)

​

Wire the relay so that the NC contacts are for the radio (normally closed, that is, the contacts that are connected when the relay is not powered). This way, if you don’t have a switch connected, the radio is active (which I am assuming will be the most desirable result.

This scheme doesn’t need any silent CD, and it isolates the sources. It also makes switching sources easy.