Jeep JK 3.8 charging problem

[austin-hill]

Hi everybody, I am new to the forum so I hope I am posting this in the right place. I have a 2010 Jeep Wrangler JKU with the 3.8. I recently had the battery light come on and after getting gas I was stranded at the gas station. I replaced the battery and was able to get home. The next day it started fine and was able to drive to work (5 minute commute) by the time I got there the battery light was back on and after work it was completely dead. I should also mention I live in northern Minnesota and today was are coldest at 1 degree F so that definitely doesn’t help. After work I picked up an alternator put it in, jumped it and it worked. I drove home and within 30 seconds of getting home the battery light turned back on, I parked it in my driveway and let it run for a while and after 3 minutes it died.

I should also mention that I did have starter issues this summer where the car wouldn’t start and there would be a clicking sound but after a few tries it would start back up.

Could the problem be the starter? I did find that bad starter solenoids can draw constant power so that’s why I am thinking it could be that. I also think it could be the wire going from the battery to the alternator. The other weird thing is after it dies it still has power but it won’t turn over but I can tell that it doesn’t have a lot of volts because there is dimmed internal lights.

Does anybody have any ideas or dealt with this issue?

 

[BLACKJKU]

Do you still have the crappy Factory battery clamps on, if so replace them with some HD ones. Make sure the battery cables are clean on both ends.

Next your going to need a volt meter and check the battery volts before you start it, should be 12.3 to 12.5v's.

Then start it and check your charging volts at the battery posts, then at the battery clamps. Should have 14.2 to 14.6 volts with it running.

 

[Snowbird Tom]

Or just stop by your local auto parts superstore and have them run a charging system test for free. I'm with ^BlackJKU - probably junk terminals at battery. First place I'd look.

Quality terminals Quadratech

 

[austin-hill]

The only problem is that it won’t charge at all, if I charge the battery from a jump start it’ll only last a little while. After about 5-10 minutes it will turn on the battery light then after that all the dash lights will light up. Then it’ll die. I also did replace the starter yesterday but that wasn’t the issue. My thought is that there could be some corrosion between the battery and alternator.

 

[tJKrider]

I also think it could be the wire going from the battery to the alternator.

This is where I would look since you already replaced the alternator.

 

[Dirty Dog]

The only problem is that it won’t charge at all, if I charge the battery from a jump start it’ll only last a little while. After about 5-10 minutes it will turn on the battery light then after that all the dash lights will light up. Then it’ll die. I also did replace the starter yesterday but that wasn’t the issue. My thought is that there could be some corrosion between the battery and alternator.

That would be a good place to start. It's also possible that your new alternator is simply bad out of the box. It does happen. If you've got a new battery and a new alternator, and the battery is not charging, the two are obviously not connected to each other properly.

 

[BLACKJKU]

Also the charging is controlled by the ECM, which can fail. I know quite a few of the Dodge truck owners would just put a 1 wire alternator on and bypass the ECM. But then you'll probably always have a CEL on since the ECM won't know it's charging, but it would be cheaper and easier then messing with the ECM getting it repaired or replaced.

 

[austin-hill]

Thanks for the tips I will start there, I will also bring the battery back and have them test it just in case it was a shot battery from the start.

 

[BLACKJKU]

Thanks for the tips I will start there, I will also bring the battery back and have them test it just in case it was a shot battery from the start.

I bought a Red Top Optima battery last year that didn't even last a month, so yes it's possible.

 

[Dirty Dog]

Thanks for the tips I will start there, I will also bring the battery back and have them test it just in case it was a shot battery from the start.

Charge your battery and get the engine running. Now put your multimeter on the battery. Does it read 13.5-14.5V? If so, your alternator and the connection to the battery is fine. Replace your battery. If it reads outside that range, put your multimeter on the alternator directly. Is it in that normal range? If it's not, then your alternator is bad. If it is, then the problem lies between the alternator and the battery.