For the steering wheel control function, you need to follow below steps: 1. Find your car steering wheel control button signal wires, it is normally located under your driving wheel. 2. The signals have two, one gives "+" voltage and another gives GND voltage. 3. Check our unit power cable, there is a wire labled "key1" or "key2"4. Connect the "+" Voltage wires to the "key1" or "key2" wires. 5. Connect the GND wire to GND wires of our unit. 6. Go to the Steering Wheel Control or SWC APP in our unit.7. Press your steering wheel control button and there will be a voltage on our unit to memory. 8. Step by step to finalize all the buttons.