I pulled the center consol out of my '90 Jetta to install an eq/booster. There are wires going to the cig lighter, and also a set of wires going to a STRANGE SILVER BOX, about the size and shape of a pack of cigarettes, that resides beneath the ashtray... what is this box???

 

I would suggest you to consult the owner's manual.there it will be given clearly.

 

The neutral can develop a voltage relative to earth if the load is not even on all phases. Since some equipment is only switched in the active lead, it is important that the rest of the circuitry is at zero potential when the power switch is off.