1997 Maxima ECM

I know this may be a dumb question, but where is the ECM located on this car or on any car. I don't know where it is because I have never needed to get wires from there. 

it is on the passenger side of the center console, there is a panel there that can be removed

The location depends on the manufacture and the specific vehicle.  GM tends to like to put their controllers under the hood, where as most foreign companies like to keep them protected inside the vehicle.  Kevin Pierson

The ECM is on top of the floor, in the front-center of the car........underneath the area where the radio is. The plug with the wires is on the passenger side, but it's tight there. Rather, if you go to the driver's side of the ECM, you can slit open the tape, and the wires are there with plenty of room to work. Just pop out the small black panel to the right of the gas pedal, and you'll see it.