92 240sx automatic - wire identification please

[brokeAs240sx]

Anyone know exactly where the thick black plug w/ white wire (attached to the red plastic piece) goes & what it does?

I think it's the power for all of the relays in the relay box, but I want to make sure.

I tried looking through the FSM (Electrical Section) & I think I found the wires in one of the Main Harness diagrams, but all it says for the black plug & green plug are "BATTERY" (I believe they are labeled as E22 & E33 in the Main Harness Engine Compartment diagram).

picture link (for some reason zilvia isn't resizing large images like it used to):
http://img175.imageshack.us/img175/292/imag0167f.jpg

Thanks!
QV

[g6civcx]

It should go to the main power for the fusebox.

[brokeAs240sx]

Any further details?

After some testing, looks like it goes into the interior (interior lights don't come on when it's disconnected). I popped open the main fuse box in the engine bay & the wire seems to go straight through (unconnected to anything in the engine fuse box).

Of course, I disconnected ALL the interior panel fuses & it still causes a drain when plugged in... must also power something else. I've disconnected all the fuses/relays in the engine bay as well.

What I'm trying to figure out is why this single wire, when plugged in, lowers the voltage of the battery about .75 - 1 volt (Odyssey battery, going to try w/ a normal full sized battery next). Regardless of battery though, I think this is the main cause of my electrical drain that slowly drains the battery after a couple days.

[g6civcx]

I can't help you much since the wiring looks like it was modified.

I suggest you trace that wire. Pull out as many things as you need.

Let me know where it goes to and where it branches off. Be extra careful and pay attention to the fusebox. It may look like it just goes right through, but it may branch off underneath the fusebox. You need to pull out and see.

I suspect that it's supplying battery power to the fusebox, but since the wiring was modified there's no guarantee.

[brokeAs240sx]

No wiring was modified. A couple extra wires have been added (completely independant of the wiring I'm looking @), but everything else is stock as far as I know.

I've pulled the fuse box & I've removed all fuses from the fuse box. Since it still has the same amount of drain, I would guess that my problem doesn't have to do w/ anything in the fusebox.

Thanks.