Defroster and tail light wire question

[mr_han_solo]

Hello,

I recently converted my '73 240z taillights and light harness to a 280z taillight. Today I wanted to check the wires with an ohmmeter to make sure I soldered everything correctly. So I disconnected the body harness from the passenger compartment and pulled out the old voltmeter/ohmmeter. Everything worked fine except for the black wire. (ground?) After looking at the wiring diagram it seems that the black wire goes to my rear defroster. Sure enough I traced the black wire from my taillights to this black wire:

    

I can see where the female end plugs in my rear defroster, however, where does the male end go? Also, I dont have another female connector/wire to go onto the other tab on my defroster. let's say I wan to take the defroster out and not use it. Could I just ground this black wire to the body and be okay?

Now for the second question. On my body harness connectors (the part that plugs in the passenger area of the dash I have two black wires that I cant trace. As I said before I have the black wires coming from my taillights and they go the the black wire that connects to the defroster. I'm wondering where these two black wires come from.

The first black wire is in the middle connector along with the red/black, green, white/green, and red/blue. The second black wire goes combines with a red/black wire into a single connector. This can be seen as the top wire (the kobalt utility knife is on it).

Just hoping someone can help me answer these questions so I can move onto checking the wire from the turn signal/headlight switch/and fuse box to the connectors in the passenger compartment.

Thanks,

Han

Edited December 5, 2013 by mr_han_solo