2007 Camry Hybrid - adding XM tuner

[dmueller]

First post.

This past weekend I added an XM tuner and Toyota adapter to the factory JBL radio. Should have been a piece of cake since it's a simple 12-pin plug-in on the back of the head unit.
After getting everything back together, I found the head unit displays seemed to be working fine (FM, AM, CD changer) but no audio was coming out of my speakers!
Took everything back apart and unplugged the 12-pin for XM. Turned on the "key" to check. Still nothing. As I sat there contemplating having to go to the dealer, all of the sudden I had sound! I kept the system "live" as I plugged back in the 12-pin. Everything was still working. I gently put the head unit back in the dash (still working) and as I was looking for the mounting bolt and screwdriver, the audio mysteriously cut out again.
Now I can't seem to get any sound (although the display works fine) whether the 12-pin is in or out. I've put everything back together and am driving the car in total silence. (with a hybrid, that's REALLY quiet)
Also, I've noticed that adjusting the volume dial doesn't display the volume level anymore. Kinda makes sense since there isn't any sound coming from the speakers, but I can't find any loose or disconnected connections.
Any ideas what might be wrong?
I'm preparing myself for an embarassing trip to the dealership. It's not too hard since there is no distracting sound coming from my car stereo.
H