kry01

I have a 97 maxima with approximately 60k miles now car's been babied so this problem is perplexing. around xmas time the car seemed to have a dead battery an optima red top so I take it to autozone the guy tests the battery says its good, so i charge it at autozone for free then put it back a day later it dies and figured time to replace it so i put in the duralast gold. That lasted for 2 days then it would not turnover so I thought maybe it was cold and not charged. So the next day it wouldn't still turnover batteries dead then i went to autozone and complained batteries trash so they tested said it was fine ran diagnostic said alternator and charging system is fine also battery is good as well but the guy was nice and replaced it. So 2 days later again the battery dies whenever it gets below 45 degrees like completely dead no juice what so ever. So now got to carry around a portable booster otherwise the car will never turn over. This has been going on for 2 months or so now and I cant figure out whats going on any suggestions? I made them pull a code says bad knock sensor but I doubt a bad knock sensor can do this .. The car starts up right away once its boosted. I need some strategies on how to diagnose this.

simreal

You have a short somewhere. Until you find it the only thing you can do is disconnect your negative battery terminal when your not driving.

Batxel

iTrader: (1)

something is drawing current when your car is off.

kry01

If you were to pull the fuse one by one and check the load wth a meter would that work in diagnosing? I figured it was a short of some kind but why does it only happen in the cold?

BIGHANK

Check the battary post connectors for any damage. !

JoeB

I've seen bad alternators do this. They can get a shorted diode inside and discharge the battery when it's not running. Funny thing is it will still charge but with limited capacity. not sure how to test for this. I had it happen on my Toyota pickup and it drove me nuts. I took the alt out and had a shop bench test it and they told me it was bad.

jbreit

when you disconnect the battery there should be a very little visible spark...basicly the radio is drawing a little power to remember your radio stations...that should be it. If the spark is big, a short is for certain.

pulling fuses as was mentioned will help you narrow it down more quickly.

wouldn't an charging system test pick up a shorted diode in the alternator..?

good luck,
jb