As always, a few quick replies with good advice. It was the #15 fuse. It had worked its way loose and was not making contact at the top. I replaced it just to be sure (many of the other fuses look a little ragged). Voila! Locks, antenna, trunk, and dome light are functioning normally again.
Sold: 1987 MB 300SDL, 320k miles, Astral Silver, Blue Leather, all books and records from day one.
Totalled: 1998 VW Jetta TDI, 488k miles, Classic Green/Gray Leather, loaded, E-Codes, "Slightly" modded, "Slightly" faster than stock, arrived 11/07/1997.
MBCA Member, Chicago Region