I'll be damned. I went in through the clock hole and carefully disconnected the harness behind the dash light. There's just enough room to get in there and check continuity with a multimeter from the end of the wire at the handbrake to the harness at the dash light. And ... I had continuity. So I plugged the harness back in, started the car and I can now ground the wire and turn the brake warning light on. Go figure. There must have been some dust or something in the harness plug.
I'm looking good for my remediation inspection.
Brian