installing after market radio, which interface do i need?
 

i have a h2 2004 and replaced the factory radio by a kenwood. i think i have a lux bose amp (no premium system) since the car is from early 2004. but i'm not sure. i live in europe an therefore have no onstar. i don't know if it has never been installed or taken out later.

we tried different interfaces from pac, but didn't manage to get the chime to work. is the chime produced by the amp? which interface do i need and what could be the reason that the chime doesn't work?

the pac c2r produces a quite terrible chime by itsself but that's not what i want and with the os2 interface the chime didn't work either.