Recently,

I was chasing an intermittent short in my break circuit. It turned out to be a dodgy wiring job in the rear, so I rewired the whole thing.

http://thumbs.ebaystatic.com/images/...Hq7/s-l225.jpg

Which is supposed to light up, and when?

I think that...

The top light turns on with the night lights are on, turn signal is on (left and right, hazard is on, and breaks are on.

Is the bottom light supposed to turn on only in reverse, or does it turn on with the night lights as well?

 

In reverse, should not be on taillight circuit.

 

So, does that imply that everything else I had listed was correct?

The night lights should turn on both the upper and lower bulbs and the top bulbs should turn on when the turn signal or breaks are active.

I wasn't sure what the triggered the power to the red/black wire that drives the lower bulbs.

 

The light at the top has a dual element. This means it can light up for 2 different actions at the same time. The lower light only lights up for the reverse circuit. Universally, the brown wire is the parking light circuit, which lights up the dim element on the tail lights, side markers and license plate lights. Yellow is for left turn signal, hazards, brakes and lights the brighter element. Green is for the right side turn signal, hazards, brakes and lights up the bright element. There will be another wire for reverse lights which only light up lower bulb, or bulb behind white lens. Lights are grounded to frame or body.

 

Sounds good. I have everything wired correctly, I'll just need to find out where my continuity is terminating from the neutral safety switch. I'm assuming that's what drives the power for the reverse lights.