I pulled apart the dash and checked the switch plug again. It appears fine. I need to get a better continuity tester though; my digital multimeter (set on ohms) kinda bounces around but then always lands on infinite resistance.
In fact, same thing happened last night when I was checking around the BR1 connector in the rear quarter panel. Unplugged, the L-B resistance to ground would bounce around and then land on infinite. It was doing some other weird things that I should confirm and document (got a test light today to do that), but I'm worried that the problem is in the wiring somewhere. I hope not. It's all in good shape, the fasteners, wiring, connectors, etc. no corrosion just a little dusty so I'm amazed there's a problem.