Alrighty, it works! Got everything put back together and went for a quick drive. Was able to enter a destination while moving and also was able to browse through my iPod.
So the green connector has a green wire with a black stripe and a brown wire with a yellow stripe. You need to insert a wire in the empty hole between these two wires and ground it. I just used a length of 18gauge wire, stripped off about an inch of insulation, twisted it up, and stuck it in the hole.
Here's how to get to the diagnostics menu to see if you got it right.