AIR/F GAUGE o2 Sensor ??? HELP

[Gmans13]

Ok I messed with this all day today and got nowhere. Maybe you guys can help me. My gauge is hooked up to good power and good ground. I lights up fine but I cant get it to work. My o2 sensor has 3 wires comming from it. Black, white, and red. I have the wire they say to connect to the o2 sensor connected to the Black wire. Could it be my o2 sensor isn't working? I drove arround with it unpluged for a few days it didn't feel any different to me. Still getting an average of 20mpg on a tank... Please help it would be much appreciated. Thanks in advance

[Gmans13]

I forgot to inclued this diagram I made. ( Please feel free to use as an example. I take pride in my work)