My alternator went bad around 2 months back. I went to the auto parts store, picked up a new alternator, installed it, everything was working fine. My xj was recently in an accident causing the door to be knocked out of wack giving me a constant (door open) light. It's been longer than id like to admit to have the door fixed due to a mixture of business and laziness. So whenever I finished driving I wold disconnect my battery and reconnect when I needed to go somewhere. Today on my way home my battery gauge reached 19 (used to hit zero before alternator change) and the check gauges light came on. Would the constant disconnecting and reconnecting be the cause of the alternator going bad. Obviously I always turned the engine off before disconnecting, or did I just receive a cheap alternator OR is it my battery that is the issue? Thank you in advance.

 

Verify voltage with a DMM.

 

x2

Also check your terminal connections. Mine went loose not long ago and when they would come off the battery or loose enough to lose connection, my volt gauge would peg out.

 

I ended up cleaning off the terminals. Now everything works fine. Thank you

 

Sweet. Glad that fixed it.