Ipod Aux Mk7

[Fi.Es.Ta]

I only have Aux connection on my mk7 and always use my iPhone to play music which is fine but when someone rings me the music fades out and the phone starts to ring through car Speakers so i use it as hands free basically.But since dissconecting my battery to install sub and amp my phone no longer rings through the Speakers it just plays music.

Any ideas will be appreciated.