I have a 99 XJ. I recently needed a new battery, less than 2 weeks old. Installed the battery and everything was working fine. Went to start the Jeep this morning and the battery was dead. So, I figured the alternator went bad, pulled it, went to Autozone and had them check the battery. Passed like a champ. Any ideas on where to look now?

The Jeep is throwing the code for the NSS, but I checked the battery with a volt meter and it is less than 3 volts. I know the NSS can cause some starting problems, but I wouldn't expect the battery to be drained. Could be wrong.

I can jump the Jeep, it is a rough start, and I have to give it gas for a few seconds until it will idle normal and not die on me.

Any info would be greatly appreciated!!

 

If the battery is new and showing 3 volts, take it back. Did you have Alt checked? When engine is running what is the voltage at the battery?

 

Yeah the alt was checked. It passed all tests. When the jeep is running the battery the voltage is a little over 14 volts.

 

Yeah, Take the battery back and have them put it on a charge and do a load test on it. If it checks out fine then you may have a parasitic draw on the electrical system. Here is a link to do parasitic draw testing. I had one and it helped me find mine.

 

I will have to look into this. Seems to be exactly what is happening in my situation. Thanks for the link.

 

Also, don't count your alt out. I had same problem on daughters car. Took the alt into orielys and had them test it four times. every time it passed. Bring home and put back on car. Start car and charging at 14.6 volts.

Now, once alt heated up, it stopped charging all together and ran battery dead. worked fine cold, just when heated up that it stopped. I put new alt on it and has been fine ever since.

Just saying, don't trust the auto store tests for everything.

 

This is true too! If you still have the alt out take it to another store and have it bench tested again. If you can, take it to a couple of places. Sometimes the equipment doesn't read right. Also don't put your starter out of the loop too. I have had a starter that was dragging a little cause the same problem. Just a few more thing to look at. You might as well check it all out so if it starts running again it won't leave you stranded. But the video can help out a lot. Good luck and let us know what you find.

 

I'll try the test with the multimeter to see if anything is pulling the battery down when the car is off. If nothing shows up on that test, I will pull the alt again and try some different shops and have them test.

 

Looks like it just happened to be a defective battery. Still going to charge this one all the way and do the parasitic test just in case. The other battery would not charge to 100% so I had that one replaced with the warranty.

 

Glad to hear. A battery should not be down to 3 volts. That's not good for them.