> I've tried contacting the dealer - but their number continually comes up
> as engaged. Perhaps they're no longer there...

Any Jeep dealer will do.
If a coded radio is over ten years old i will write the code in paint marker
on the radio casing, It makes things a lot easier for techs, and anyone
stealing a radio that old is probably doing you a favor.
--
Stupendous Man,
Defender of Freedom, Advocate of Liberty