Tg22ar

Have some work to do this weekend on the IS-t. Finally got my invidia Midpipe/axleback combo which will be installed at my uncles shop tomorrow. Then this weekend I'll be installing a Megan racing strut tower bar that I picked up, and then finally my defi boost gauge (mechanical racer gauge). I'm curious about which wires will go to which fuse(s). Here's their install diagram. I can figure it out, but I just want to be sure before I get to it. It has 4 wires (pic below) Red, Black, orange and a white.



I know that red will be a constant, black ground, orange to a switched fuse, but unsure about where to to connect the white one. Any help would be fantastic, I'm trying to knock it out this weekend.

Tahnks clublexus