I have almost the exact same problem with my ‘65. Everything works just fine but the dash panel. Turn signal indicators (no problems with the actual lights. They all work fine) light up when the head lights turn on, only one dash liight comes on, and the high beam indicator is backwards, fuel gauge suddenly pegs on empty, and the power to the lighter socket drops to around 7 volts. I’m working it out a little at a time, and will check the steering column connections and the fuse block (again) before I pull the dash bezel. Definitely a ground problem under the dash. I’ll let you know what I find. Car show on Saturday, so I’m doing a lot of little cosmetics first!