Ok, I messed around with it some more and the shop that originally installed the empeg in the car cut the 12v/ground wire that the radio module plugs into. I spliced those back in and it now sees the radio.

The problem I'm now having is I can only hear it (and just barely) when it is at around +10db.

Everything else plays fine through the system, but it seems like the radio is not being amplified almost at all.

The wife has the car right now, but I'll mess around with it some more later.