Wanaron

Had trouble free motoring since buying the jeep, have always sung it's praises, without doubt the best 4x4 I've ever had,,!
Without any warning the battery was totally dead this afternoon; hasn't been slow cranking over or give any warning at all! Not even enough power to light the ignition lights"!
In my experience a failing battery has always been a gradual process, has anyone else experienced such a sudden failure.?

Wayne

Bustedback

Could be dirty connections at the terminals, but it seems since fuel injection and more electronic gizmos have become the norm, batteries don't give much warning at all.

Wanaron

Thanks for the reply, tried all the obvious things; dirty/ loose terminal connections, even got the wet n dry out n cleaned em up, to no avail,
Just ain't ever known a battery give no trouble or any sign and be totally dead like this,!

dave1123

Yes they can, but it's unusual. I had one that had just come in from a long trip with no problems. We went to restart it and there was a "BANG" from under the hood. All the caps had blown off the battery and it was dead as a stone. I stuck voltage probes down each hole and one didn't give me a reading. An internal cell connector had shorted out and melted, igniting the hydrogen and blowing off the caps. That battery was only 2 months old and a Delco.

See if it will take and hold a charge. If it will, check for power draw with the ignition off. If you've got more than 0.75 amps, start pulling fuses until you find the reason. The only thing drawing power should be the PCM and radio memory.

Wanaron

Not long in from work; had the battery on trickle charge for well over 24 hours now! Put it on. Connected her up n started first attempt! Lost the light now so not really practical to start pulling fuses now to find what draining it. Have to wait n see if holds power till tomorrow.
Have checked voltage not running is 12.42 volts; engine running with a few revs goes up to 13.72 volts! So it appears that the alternator is doing its job!
Understand radio memory drawing a little power; can you tell me what "PCM" stands for?
Thanks

dave1123

PCM = Powertrain Control Module or "brain", computer, black box.

There are a few others, like

TCM = Transmission Control Module. On your WJ, the TCM is now part of the PCM.
BCM = Body Control Module

Somewhere on this site, there is a complete list of acronyms or abbreviations for them.

Bustedback

A battery at 12.4 volts is discharged, 12.6 is the minimum voltage for a fully charged battery. I know .2 volts doesn't seem like much, but it's a pretty big deal when you only have a 12 volt system.

Wanaron

It's gone n gotten a whole lot worse,!
Put a new battery at the ready In the boot( trunk). Spanners at the ready should the recharged one lose charge- was alerted by a kind passer by as I was in a restaurant with wife n some friends last night- that my jeep " was on fire" !
Rushed to it and indeed smoke was coming from under the bonnet( hood) and after a good dousing with a fire extinguisher, and disconnected the battery. It was plain to see the. Lead from the positive side of the battery had got mightily hot! Outer casing black n brittle,!
Upon further inspection a greenish liquid was escaping from somewhere? Not much but still there,! Heat screwed a pipe?
I'm led to believe that the lead Must have been bare somewhere, n touched the metal causing a short circuit!
Had it towed in today n await the verdict! Won't be at all happy if it's screwed; one lovely n up to this point very reliable jeep,!

dave1123

OUCH!! Let us know what you find out so we can warn others. I hope it didn't do too much damage. Battery fires are not fun. If a dry chemical extinguisher was used, just getting the powder cleaned up is a lot of work. Make sure it's cleaned out of all electrical connectors.

This may not have anything to do with your experience, but I worked at Valvoline Instant Oil Change at one time. It was a busy Saturday and we had cars lined up outside waiting and I was working in the pit. here was a Ford Escort next in line and the lady had popped the bonnet catch before coming in. She was just sitting there with the engine shut off and I noticed smoke coming out from under the bonnet. I could see flame as well and I screamed "FIRE!" My boss grabbed an extinguisher and sprayed it into the crack under the bonnet and then opened it. The flame re-ignited and he sprayed it again, then someone disconnected the battery with a heavy spanner by smashing at the cable.

The alternator had shorted out and caused the fire. The lady stated she had just come from Sears after they had put a new one in! We called Sears and they towed it away. The entire front of the car was covered with white powder like someone had hit it with a 5 pound sack of flower. The lady came back a couple of days later to thank us and tell us Sears couldn't repair it and gave her enough money to buy a NEW car! I guess they decided they didn't want the bad publicity. Valvoline really put on a show for the other customers that day.

It doesn't sound like yours is that bad and I hope it isn't.

Wanaron

Well got the call to say Jeep was ready to pick up, one relieved guy I can tell you!
Problem was as most people has said was the battery shorting out, however it hadn't touched the body or similar- it had chafed against the air conditioner pipe; roughly halfway down the engine bay between positive side of battery and starter motor. It actually burnt a hole in AC pipe! Could have been a burnt out shell if that guy hadn't alerted us to it. Might be worth members of This forum checking that this isn't happening on their Jeep!
A thorough clean up; lead now cushioned so can't occur again! And it appears so far anyway that nothin else has suffered as a result. Was worried that it may have creAted electrical problems, or taken out alternator or starter motor
As I say guys take a look! Might be a wise and motor saving thing to do!
Wayne

dave1123

Thanks for the heads-up. It's surely something to check. The engine compartment layout may be different on ours because we don't get to play with diesels, BUT there is not much clearance between the battery harness bundle and the AC hose on my '00 WJ 4.0. Now I'm nervous about the fact that ALL the electrical wiring in that area is bundled into a fat harness about 1&1/2" in diameter! That includes both the hot AND ground battery cables.

Wanaron

The guy who fixed mine has sleeved the battery positive lead right the way down in a rubber hose! Not takin any chances of it chafing n shorting out again,Will certainly be looking and making sure it's ok going forward! I like my Jeep,! N that was scary,!
Got another problem that's unrelated to the battery one; so probably best start a new thread!
Thanks