Battery Light, for the second time

[osufans]

OK, so have a weird issue. My battery light came on a few months ago, and when inspecting under the hood, I noticed my negative terminal was a bit loose, and also corroded.

I have actually had to clean the negative terminal once before due to heavy corrosion.

So anyways, I don't remember if I had already done this before the first time the battery light came on, but I have since cleaned and then sprayed the terminals with that corrosion inhibitor (red spray stuff).

So today, several months down the road, the battery comes on out of the blue. I popped the hood once I was parked and checked the terminals, and didn't noticed anything loose, but did notice the negative terminal is turning green, but no heavy corrosion yet.

So I go into the store, come back out, and the Jeep starts fine, no more battery light. WTH???

The battery looks new, I'm pretty sure it was put in by the dealer just before I bought it. I've never had any problems with starting or an apparent weak battery.

So two questions....first, any ideas on what my issue could be? Second, what would cause that much corrosion to build up? Bad ground somewhere?

Thanks for any insight!

 

[tommudd]

Battery could be leaking a small amount, vapors will cause the corrosion to build up along with loose cables

I would say its the battery no matter what it looks like

 

[osufans]

Stopped by the auto store on the way home and had the battery tested. They show it as being fine, but said there was a .75 amp draw after turning off the key. However, I didn't open the door yet, and I'm pretty sure the system stays on for so many secs until you open the driver door, so I'm thinking that's all it was.

I'm actually thinking it is a bad ground, as I have read some other reports of a bad ground causing corrosion. When I bought it, the negative terminal was extremely corroded, even up into the crimp and starting down the insulation jacket. There was corrosion down the side of the battery, in the tray, and on the fender well. I'm thinking the previous battery was bad, maybe leaking, and caused some damage to the negative battery cable.

Along with that, I've always heard its not a bad idea to upgrade your grounds anyways. I may try that first.

I haven't looked yet, but is there a how-to on upgrading your main grounds? I've heard it called the Big 3 on other sites.

Thanks!

 

[JeepINgeek]

upgrading grounds is a questionable mod. when i did it to my PT i saw a veryveeeeery slight improvement of light dimming.. some say it improves performance.. some say its snake oil.

 

[osufans]

yeah, i did more searching on the net for causes of battery corrosion, and regardless of other issues, most every site mentioned gas venting as the primary cause.

i'll have to take the terminals off and see if either of the posts are loose, and clean the negative wire thoroughly.

the only reason i'm not sure it's gas venting is because only the negative terminal is having the issue.

 

[Dave]

Battery could be leaking a small amount, vapors will cause the corrosion to build up along with loose cables

I would say its the battery no matter what it looks like

I am inclined to agree with mudd here.

If your neg cable is getting corrosion and such then take the cable off and look real closely around that battery cable connection post for a possible hair line crack.

Just a thought.

Dave

 

[tjkj2002]

1st clean off all that corrosion inhibitor stuff,makes things worse and causes issues also.

The battery light means a problem in the charging system which can only be checked by the DRBIII if your KJ is a '02-'05(Starscan for newer).No other way to diag the system correctly since it is PCM controlled.The battery is the only part of that system that can be tested by other means then the DRBIII(or Starscan).

 

[LibertyTC]

The stock oem batteries have removable caps. Often owners can overfill those batteries when they think the cell needs more distilled water, causing more venting than necessary. Look inside the caps to see if acid/water level is too high. Should be about 1/4 inch above the plates.
Also below the battery is a pad with wires, that is a temperature sensor. I have heard that the battery light may also come on if those wires or pad get corroded.
Make sure your terminals are clean. Heavy corrosion should be first dealt with by using baking soda/water paste to neutralize the acids, then generally clean the terminal with a wire brush/ emory cloth to get the terminals HJ polished. I apply Vaseline to the terminal ends, with good success in keeping corrosion to a minimum.