I have an AVIC-Z110BT with a GEX-P920XM tuner. The GEX antenna is mounted on the roof. While I have adjusted the volume level for the XM so it matches the levels for FM/CD/iPod, the XM sound is always monaural never stereo. Anyone else with this issue? Any ideas?

XM sound is not the greatest but it does come out stereo.

Actually, it doesn't ... at least in my set up. You can hear the stereo with FM/CD/iPod ... but when I switch to XM, it's a flat, monaural sound.

XM does output in stereo. It's easy enough to verify by moving the fader from left to right.

I have done that ... and the sound out of each channel is the same (vs. doing the same test with FM where the difference in the two channels is obvious). I also did a resrt of the AV on the AVIC unit without noticeable change. Someone suggested there was a reset button on the GEX tuner, but that is difficult to get to. Anyone know what resetting the GEX box actually does?