Unbelievable!
OK, first the fuse was in the battery bay. On the forward wall are three fuse holders each with two fuses. One fuse (15 amp) is marked BCR. (Wow: Brake Control Relay.)
Fuse wasn't blown. But when I went to plug it back in I noticed the terminal had pushed well into the cavity and could not make contact with the fuse. Pushed the wire back into the holder, reinserted the fuse and dang: it works just fine now.
Now to go back and re-loom all the wires I took apart to try and trace that blasted thing!