I don't have a Maxima, but I'm sure the Max isn't too much different then my 300ZX. I hard wired a radar detector and a mobile police scanner in to mine just by using the cig lighter. In the back of mine, the power wire connects in the back and the cylinder part is metal and it's the ground. One wire gets mooshed in the little bullet plug for power, and the other got taped onto the ground. Done.