One of the wires is orange and the other is white at the brake light switch. Shouldn't there be an orange wire hooked up at the "S" terminal on the light switch? If so, where does that go?
You're right, it seems that both filaments are lighting up.
This is a bummer, I was so careful when wiring this up, now it looks like I need to unwrap the wires to see what I did wrong. At least I can drive it during the day!