i have come across many ipod interfaces that have been a little tempramental with things like this...not just a fault with Alpine itself but has been the case with several other brand interfaces also. Usually if you just pull out your head unit and unplug the interface, give it a moment during in which time assure everything is switched off. then reconnect the interface and place comfortably back into the din slot of the dash assuring that no wires are being compromised or squashed behind it!
Failing that and it continues to persist, then it may be worth contacting Alpine for some troubleshooting tips. If u stil have the box and user manual to the interface, usually explains common faults in there or directions in the event of functionality issues!
See how u get on with that. Otherwise if still no joy then u have no other option but to return/ take it bak to where u purchased it! goodluck!
