Since the release of Apple products and in car multimedia products which allow connection of your iPhone or iPod, customers have had problems were they have had a double din multimedia system or a Parrot hands free installed in there vehicle and they plug there white lead in the USB and no music plays. This is not a fault with the multimedia or hands free system it is down to the customer using a fake Apple product. There is a slight difference in cost with a fake Apple lead from ebay for example costing around £4 and the official Apple leads costing around £20. The problem is the cheap copy leads provide charging but don’t allow music to stream through the cable.
The Official Apple lead has a small microchip which allows your Apple product to send music from the 30 pin connector to the USB connecter the end which you would plug into your vehicle. Cheap and fake leads are easy to spot due to the colour of the plastics not being a matt white colour and the wire used is not very soft. The best route to take is go to the Apple shop and buy the official lead to not have any problems.
And there is another issue which can cause music not to play the first time you plug your device in. All you need to go is carry out a soft reset which will then allow a perfect connection.