I just bought an air/fuel ratio gauge that hooks up to my stock rear o2 sensor, and i dont know which color wire is the signal wire. Does somebody have a diagram or something of which color wire does what?

Step 1: Find receipt.
Step 2: Return said gauge to Autozone.

Seriously, that thing is useless except as a light show, especially if you use the rear O2 sensor. The rear O2 sensor is pretty much only for emissions, to ensure the cats are working correctly. The front sensor is what your ECU uses to trim fuel in open loop mode, but even then, it's only accurate in its narrow band (~12-16:1 I think?).

A wideband O2 and gauge is more expensive and harder to install, but will actually be useful.

Well first i didn't get it from autozone. I know that its not going to be as accurate as a wide band but i just got it to get a general idea. So if it hooks up to the rear o2 sensor why couldn't i just hook it to the front one instead since you say its more accurate. Are the wires the same on the front one and rear one?

I suppose you could hook it to the front, it would then have some semblance of usefulness. scoobymods.com should have a writeup to install it.

Though I'm not catching the point of it- in open loop, the ECU will keep it around 14.7:1, and throw a CEL if it can't. In closed loop, you'll most likely have an AFR that will just read 'rich'- beyond the range that a narrow-band can accurately read. If you're not using it to tune, what really is the point?

Firebox is 100% correct on this. The tap-in gauges are of NO use for any meaningful readings.
The front 02 is a special semi-wideband type and cannot be tapped into, if you attempt to do so you won't get any readings and the ECU won't get a proper signal from the 02 so your car won't run correctly.
The rear 02, aside from being narrowband, is too far back in the exhaust stream and is also behind the catalytic converters.
Further unless your car is significantly modified you don't really need to monitor A/F. Once you have enough mods where such monitoring becomes necessary, then the addition of a wideband setup is warranted.

Well i didnt post this thread to get bashed. I got a really good deal on a gauge package and i got a boost gauge, A/F, and EGT gauge. All i wanted to know is if you guys know how to hook it up. These are the gauges i got. I dont feel like spending the money on a wide band right now and i have no use for one. I just wanted to monitor my A/F and get an idea of what it is. I have to put it in or i will have an empty hole in my A-pillar mount so i have to hook it up. Just wanted to know How!

you realize you can screw up your car, and potentially blow up your engine, by installing that O2 and tapping the sensor, right? Your ECU uses that for fuel trim, and by splitting the signal, you are changing it some. The gauge could also induce noise into the line, giving your ECU false readings.

Firebox just said that your car uses the front o2 sensor for trimming fuel. why would it hurt anything to hook it up to the rear o2 sensor?

Firebox just said that your car uses the front o2 sensor for trimming fuel. why would it hurt anything to hook it up to the rear o2 sensor?

Rear would be safer, but since it is downstream of a couple catalytic converters, your results are pretty much useless.

What if i am running a cat-less DP.

Well i didnt post this thread to get bashed. I got a really good deal on a gauge package and i got a boost gauge, A/F, and EGT gauge. All i wanted to know is if you guys know how to hook it up. These are the gauges i got. I dont feel like spending the money on a wide band right now and i have no use for one. I just wanted to monitor my A/F and get an idea of what it is. I have to put it in or i will have an empty hole in my A-pillar mount so i have to hook it up. Just wanted to know How!

No one is tryng to bash you. They're giving you good solid advice. If you want to install it, as was said earlier, you can go over to scoobymods and there are some writeups there as to how to do it. That said, I agree with the others that this is generally a waste of time to install, and generally pointless. I suppose as a filler for your gauge pod would be amoung the more advantageous uses.

What if i am running a cat-less DP.

The uselessness of using the rear sensor is less about the cats and more about the sensor. The rear sensor is ONLY there to tell the ECU that the cats are working, and as such it has a narrow range and poor resolution.

BTW, what gauges are you using? There may be another more useful gauge you could stick in there, and sell that AFR gauge to some ricer on ebay.