I'm just wiring up my AEM 30-5130 gauge and it also has a brown wire labelled analog. In the instructions it says to wire the white and brown wires to a data logger. So now I'm confused. Should I be taking the white wire back to the old O2 sensor green as mentioned above (is that the Lambda + input)? If yes then what about the brown wire? The instructions say it must be used if the white is used. Ideally this brown would be connected to the Lambda - input if there is one or to a sensor ground if no - input or finally to a chassis ground if none of the other two exist. Who can help answer my concerns?
http://aemelectronics.com/files/instructions/30-5130%20Analog%20Wideband%20UEGO%20Gauge%20Gasoline %20AFR.pdf
Thanks, Mark.