I just bought a V.W ISO-8Pin USB+SD MP3 Adapter,so cool,now share with you the installation.Hope it can useful to you.
1. Pull out the unit from the car and touch the back of the unit for CDC port when the ignition is switched of.
2. Insert the CDC plug into the original car port correspondingly. Then insert the storage card.
3. Then check if the device works normally or not after power supply given from the car itself.
4. Put the wire harness into the proper and good place after the test successfully.