Using the 30 pin adapter unable to access music on the car

30 pin adapte connected to what exactly?

Also iPads are not normal MP3 players, as such they don't have a regular file system the car media center can read to get music files.

You may be able to play the music through bluetooth if the car supports it. Or have the iPad send the music, but the Car media center will likely not be able to actually index the files in it.

How are we supposed to help with what little you have provided?

The iPad mini has a lightening plug - so I guess he means a lightening to 30 pin adapter.

Yes i know, but then what is it connected to on the side tha is not plugged into the iPad? And why? The lightning cable ends in a USB just like the 30 pin one so not sure what we are talking about here. What is the adapter connected to?

More details would be nice to have.

I'm just guessing (like everyone else) that he has an FM transmitter with a 30 pin plug which he needs to connect to his iPad mini

"Guessing" being the operative word. In which case we still need more info before we can provide an accurate answer.