Reverse Gear Sensing Wire

I have a 2000 Nissan Pathfinder LE and I'm installing an AVIC-D2 in it. I've come to the point where I need to hook up the Reverse Gear Sensing Wire and my problem is this:

I was told the wire I need to hook it to was a Yellow (+) Wire in the 20 pin connector under the passenger side kick panel.

I pulled back a little of the insulation on the yellow wire in the 20 pin connector under the passenger side kick panel and took my meter connected one side on the wire, the other on ground, switched into reverse... and... nothing happened. No change, still 0 reading on the meter.

I double checked this 50 times, checked my meter, checked everything. I even called Crutchfield to see what they said, and they also said I was doing everything right.

So I took apart my taillight and in the wires going to the reverse light there is a yellow wire that looks exactly like the yellow in the 20 pin connector, and all the other wires in the light resemble wires in the connector up front.

So I did a continuity test and it seems that the wire in the back and the wire up front, although they look identical, they are not the same. I tested the wire in the back and when I switched to reverse, I got a reading of 12 volts.

So now, I know I can run a wire from the taillight up to my D2, but do you guys have any clue why this isn't working?

I would appreciate any and all answers as this is driving me crazy!

Thanks.