════════════Frequently Asked Question════════════
Author: sany081
Reason: topic

Good health to all.
I want to show you how to make the stock head unit control module work with other head units that have a 3.5 mm mini-jack connector for controlling the head unit.
I have a PIONEER head unit, but there is also a wiring diagram for SONY. The only difference there is in resistors, specifically their resistance.
Here's the resistor scheme for the PIONEER head unit

resistance scheme for Pioneer GU

resistor scheme for the SONY head unit

resistance of resistors for Sony GU

We disassemble the control module of the stock head unit and take a variable resistor (commonly known as the volume knob) and disassemble it.

then another 4 screws

remove the retaining ring

and remove this part

this part is what we need

Then we need to break the resistive layer in two places to reduce resistance

well, that's the main part done and now we start assembling.
Then we need to resolder two contacts by swapping them

then disconnect a contact and solder it to the center of the variable resistor

and you can assemble the control module block if you don't have the ability to install resistors directly in the block.

We get the following pin connectors on output

I connected using connectors that were left over from changing the headlights, but you can also use terminal blocks. We start installing resistors with the required resistance which will control your head unit buttons of your choice. The resistor scheme for what they do is above.

insulate

solder them together as per the diagram

insulate again

for the lighting of the control module block, I also made a connector for ease of removal

taking wires from the original connector where it is marked green and one wire from ground, which you take - this is your idea. Also removed all the fluff and connected the head unit via ISO cable, here's the stock pinout scheme

And we connect everything and enjoy


The inconvenience is volume control as it controls in extreme positions. But there are ideas to use from a head unit or something else for constant control. If you have such an opportunity, then try. It will be easier and more convenient, with fewer complications.