I'm happy to report that the used AUX2CAR system for my 2003 1 CD headset I purchased from GMJAP and just now installed, went in without a hitch. Works and sounds great. GMJAP had informed be that someone from here had reported that the #6 dip switch will increase the volume. Yes, indeed it does. Also you can switch between a CD and the ipod with the CD/AUX switch, that's very nice. The hardest part was mounting the AUX2CAR box. I taped and tie wrapped it to the air vent. Hope it stays up there. Now I have to figure out a great place for the ipod. Currently it's in the glove box. Thanks again to GMJAP and all the others that posted great info here. Could not have done this without you all.