Well, finally got the problem fixed! 1Thunder you are the man!
It ended up being the PDC. I decided to take it apart myself to have a look. I found the "repaired" portion on the main board and almost had a fit! Part of a trace had been burned off so the mechanic soldered a wire from a small piece of the trace that was sticking up off the board to the pin where it originally went. Big blob of solder on the end of the protruding trace! 3 or 4 months down the road and that would have corroded off!
Once I discovered that the trace had been burned off, not corroded off, I put two and two together. FCM went bad, then burned off the trace on the board. Simple solution: replace PDC and FCM. Swapped in a new one tonight and all is well. Horn blows like a $20 hooker!
Hope this helps anyone with the same problem.... not a cheap fix though.
Thanks again 1Thunder and RIP