This is Peugeot 306 steering wheel remote controls.

Peugeot 306 steering wheel remote controller is not resistive. But you can easily modify it into resistive to use CarPC JoyCon EX.

This is the connector of Peugeot 306 steering wheel remote controls.

As the connector shows, the output of the connector is not digital yet.
This connector is connected to a control board and converted to digital for Car Audio.
But we will modify it to resistive.

This diagram shows the wiring.
The connector of steering wheel remote control is connected to Resistive Button PCB instead of original control board.
Then the button signal is converted to resistance so that it can pass through the Clock Spring of the steering wheel.

The Black wire is GND and white wire is DATA. Let the two wires pass through the Clock Spring of the steering wheel.

Black wire is GND common, the other wires are from each buttons.  

Connect the five wires to the resistive button PCB.

The Resistive Button circuit is very simple. We use only 4 switch at this time.

This show the whole connections. The black and white wires of CarPC JoyCon EX passes through the Clock Spring in real installation.