Battery drains out while driving

I had a funny story, 1998 to 2001 has known issues for the instrument panel just shutting off down the road. I had that issue and I removed the cluster to fix it myself. In the mean time I drove the car and then it was not turning on (drained battery). I jump started and then checked the alternator with a voltmeter, it was not generating. Then I put the cluster back and was generating, double check that the connections from the wiring to the instrument cluster are properly seated otherwise will not charge the battery. Also, if is not generating and the charge light is off that is must likely the issue.

I have a 1999 Frontier four cylinder and had a similar issue with the alternator not charging. I assumed it was the alternator and installed a new one. Still did not charge. After much trial and era I found that the feedback circuit for the alternator was not getting a signal to the alternator to charge. Turn out to be a broken wire at the alternator wiring harness plug inside the insulation. If that is your issue you will have to put new wires into the connector. They do not sell one separately and try to get you to buy an entire wiring harness. If you are lucky the wire should pull out the back of the connector. There are two wires on the 1999. The green wire tells it to charge and the yellow wire controls the voltage. I have had issues with both at one time or another.