Defi racer boost gauge wiring.

[El Gallo]

Hey guys whats up?? Well, its time for me to swap my mechanical autometer boost gauge for my new Defi racer electronic gauge. I have a small dilema with this. There are 4 wires from the gauge which are:
 Red- constant 12v battery.
Orange- 12v ignition on.
White- Illumination. (to 12v wire when small lamp is on).
Black- Ground.

I know where to tap for the RED wire. This will be tapped where the  LC-1 wideband are tapping into which is the MPI relay 12v wire. The Black wire will be grounded to the chasis right near the fuse box. These are easy. But what about the White and Orange wires??? Where do you tap these to?? I know its the illumination and ignition wires but where? which ones are they and location?? This is where I'm lost.
I appreciate any help.

[Ibbanez]

Correct me if I'm wrong, but couldn't u use those identical wire from your radio harness?  They have the same Wires on all wire harnesses for aftermarket radios....  Now there may be others, like for 12v switched power wire, I tap into othe fuse box in the cabin on one that only comes on when the car is on, like wipers or something else along those lines.  I have these nifty little fuses with wires on the end and have spots for extra fuses for the orignal fus e and tne for the new wire.

[El Gallo]

So how then do you think I should connect the 4 wires? Tap them to the fuse box? If so how? And what fuses?

[El Gallo]

Oh. I believe you are talking about the littelfuse ato add a circuit fuse kit. Oh yeah. Almost forgot about those. Yes. They are like a fancy fuse holder that can house 2 fuses with a wire coming out. One for the original location for the car and the other one for the fuse that connects to the wire. This allows you to connect a wire/circuit to the fuse that is power by the desired voltage that you are looking for.  I completely forgot about these little demons.  Now, my thing here is, will the add a circuit fuse fit when the fuse box is closed?? My reason for this is because there will be 3 wires coming out of the fuse box. Wouldn't the wires get on the way of the fuse box lid??  One more thing?? what size fuses should I get for the add a circuit fuse kit?? I'm assuming the same as the origials that are being pluged into.   

[1gdsmman]

the add a circuit fuse links that I get from napa and advanced auto lay down flat so the lid will close. you may have to trim a notch in the lid or you can get creative and feed the wire thru the bottom of the fuse box to the add a line. as for the fuse rating I install guages a few times a week and all of them only require a 3 amp fuse. so whatever fuse you pull put that in the lower slot of the add a line and a 3 amp in the top slot. most guages only draw 1.2-2 amps. hope this helps

[El Gallo]

This is very good. Thanks 1gdsmman!!  Though I'll be using a multimeter to check which fuses to tap/fuse into. Would you by any chance know which fuses produce a:
-Constant 12v.
-12v when ignition is on.
-12v when lights are on/dashboard lights.
This will give me an idea as to what fuses to tap into. If you don't know then its good too.
Either way, thank you 1gdsmman for responding and you too Ibbanez.