On the 1985 300zx non-turbo z31 behind spare tire there is a silver box with 2 switches on it all says Niles Japan what this for please answer asap?
The silver box with two switches and the label "Niles Japan" behind the spare tire in your 1985 300ZX non-turbo Z31 is the antenna amplifier. It is responsible for amplifying the signal received by the radio antenna and sending it to the radio receiver. The two switches on the amplifier control the power supply and the antenna selection.