rem turn on always hot, but less than 12v

On every wiring diagram I can find for my car (2006 BMW E46 330Ci Convertible) it shows the white solid wire, #10 in the grey connector to be the radio to factory amp turn on lead. BUT when I check it, the wire is hot with ~10.5v as soon as the car is put in accessory, with no difference when the radio is energized, still ~10.5v. I tried every other pin and none have any power (12v or even close) once the radio is turned on. There isn't a power antenna either on this car, strangely. Anybody have experience here?? Thanks, Radar RadarContact

Directechs show a black wire in pin 13 of a 16 pin plug at the radio

blanx218 wrote: Directechs show a black wire in pin 13 of a 16 pin plug at the radio

Ok, that's good info. Thank you! I have complete access to the other, amp plugs, side of the wiring. Did you happen to see anything there?RadarContact