I have a F150 Lariat 04 and just change the original head unit w/o mp3 to a f150 (2007) audiophile with mp3 the problems are no longer works the steering wheel control and the volume not downs when the rear sensors sound,:what wrong?

 

You need interface module for the steering wheel controls

 

No you dont need a module.

You need the unit reprogrammed.

 

And only the dealer could do it?

 

Certain dealers can. You will have to ask.