Please help URGENT!

[Acuratechva]

as we speak iam wiring up RB20 in to S13 SOHC. Everything is great except for one part. I have read 3 wiring wright ups and none of them are clear. "FB White  White/Purple (Thick wire)" everyoen is teling me to wire up White purple (wire which i have found no problem) on RB to a white wire at the fuse box... what i dont get is which ****ing one wire do i soder it to on the fuse box there are ****ing at least 5 going to it! I cant find info on what this wire is for ...is it a simple power wire?

someone please help me i am in a rush! i let my friend use my shop to do the swap and i need to get it out of here TODAY

thanks in advance!!!!

[Acuratechva]

ok i did some more searching and found that that wire is for the ignition relay... but there are no white wires going to any relays altho there is white wire going to 30 amp fuse for the IGNITION SWITCH. is this what ppl were refering?