retaining the onstar when removing radio

[03limitedgtp]

I have a 2003 gp and I was wanting to replace the head unit but don't want to lose my onstar has anyone found a way to keep it?

 

[Tony Mendez]

You'll need a interface to retain your On Star and RAP features(if equip'd). I had to put one in my 04 GTP

 

[KeithGTP03]

RAP doesn't need a special interface. Do you have Bose as well?