I've noticed the light out indicator, turns out it's my brake light. The taillight would still light, but the brake light would not. Silly me, I bought four new LED bulbs only to find out there are only three slots for bulbs, tail/brake, back-up, and indicators. I am assuming this means the break and taillight are both just one bulb.

This makes sense, but why would my taillights work, but not the one brake light?

Hmm...

 

Nevermind--I got it. Dual-intensity.