'01 Xterra 4x4 74k miles.
When you open the door there is a clicking noise coming from underneath the dashboard. Engine won't turn, lights don't turn on and nothing really responds. We tried jumping the car but nothing happens. The interior lights flash in time with the clicking underneath the dash board. I think it is coming from what seems like a black relay underneath the dashboard on the driver's side. Any ideas?

You have a bad battery I think. I won't hold a charge. Go to a larger Autoparts chain with the battery and have them test it.

How to install spark plug wires into a 2002 nissan xterra v6

Unplug the old ones, plug in the new ones. Do them one at a time so you don't get them mixed up.