Which Blitzsafe box do you have? The BMWX/ XMD 100? Unfortunately I don't have any experience with that one. I have the Blitzsafe BMW XMDMX PIOV.1. It allows you to connect a Pioneer GEX-FM903XM reciever to the CD Changer harness. It doesn't give you a display on the headunit-- so I have to use the unit controller that came with the reciever. I had some issues finding the right harness, once I located the install was straight forward. There is a warning in the installation instructions on most of the Blitzsafe units that warns that the 3 wire Cell phone wiring harness is almost identical to the CD Changer harness except for the color of the #2 wire, and plugging the Bliztsafe interface will damage both the cell phone system and the blitzsafe box. Not sure if that is your problem, just a note a read with the unit I have.