Hey everybody, hoping for a little help.

I'm replace my stock boost gauge with Omori. I have a mech. boost and EGT. The problem I'm having is finding a positive wire that is headlight triggered to tap into for that gauge lights. The wire that the original gauge doesn't work. I found a wire coming out of that fuse box under the dash thati s headlight triggered but that wont light them either. I used my test light to get a pos feed right from the battery and that will light them. Is there maybe just not enough voltage for two gauges? I thought about getting a switch from Radio Shack that is electrically triggered and an inline fuse but that just seems a little hokey. Any help would be greatly appreciated.

Which Omori gauge do you have? If it's a mechanical one you should be able to connect the illumination to the same place as the OEM gauge.
If it's mechanical, is it standard illumination or the full color type?

It's the mechanical with the full color. I tried the wire that were hooked up to the stock gauge and it wont light it. That is what seems so strange. The stock ground and my test light on the battery work. I talked to the shop I got them from and they gave me some advise. I'm going to re-ground them to the dash chassis and he uses the illumination wire for the fog lights at the switch and never has any trouble. So I'm going to give that a shot now.

I just recently installed the 45mm full color as a direct replacement for the factory boost gauge in the 3-gauge pod, and I connected the illumination directly to the existing connector that was plugged into the original gauge. The Omori gauge illuminates and dims properly using that connection.
There are two points you need to bear in mind- first, that the full color gauge uses LEDs not bulbs so polarity is critical, second that the Subaru dimming system is a variable negative NOT variable positive.
To make this work, test the illumination wires from the old gauge and verify their polarity. Then, connect the positive to the white wire on the Omori, and the negative to the black wire. Do NOT connect either to a direct ground. Follow this and it should work.

Looks liek I got it figured out. Thanx for the help. Must have been a ground thing. Like you said they are LEDs and it must not have liked a dimmable ground. I went right to the dashboard chassis and they work. But it wouldn't be like me not to screw something up. I didn't look at the directions well enough and ran the power wire for the EGT gauge function along with the illumination to a headlight switched feed. So the gauge only works with the lights on. But that is an easy fix. Thanx again for the assistance.

The mechanical boost gauge will work fine with the variable negative. The only electrical connection to it is for the illumination and it doesn't know the difference between varying the positive or the negative, as long as the polarity is right.
However if you try to connect an electrical gauge the same way you will have a problem, since the illumination shares its ground/negative with the gauge electronics so you cannot use the Subaru dimming circuit unless you add a circuit to reverse the polarity of the dimming voltage.
So, if you have a combination of mechanical and electrical gauges, only the mechanical can have working dimming.