New to the site. My wife owns a 01 Xterra with 150K miles. I own an 04 Titan. Just thought that I would come to the site and look around. The Xterra has had a few problems here as of late. Not cranking, dying without warning, and the lights on the instrument cluster going nuts as well as the in dash 6 disc CD changer. Thought that I would do some searching and see if anyone else had a similar problem. Found that the fuel pump switch on top of the tank located underneath the passenger side rear seat could corrode and break, causing shutdown. Took a look the other night, but couldn't get the plug off to look. Gonna have another go at it once I have some free time. Reckon it could be caused by a loose ground somewhere? If anyone else has had this problem and has had it fixed please let me know. I would like to know what was done to fix the problem.

Sounds like a ground issue. Remove the battery terminal leads, look for corrosion, clean with wire brush.

Could also be the alternator. They are a common problem in Xterras. You can get a replacement stock 80amp unit, or you can swap in the 120amp from a Nissan Quest (with minor modification).