06 Liberty - Battery Light - Still on after alternator and battery change

[RexSmith]

Hi all,

My daughter's 2006 Liberty (appx 250k miles) has intermittently had the battery light come on... (She lives in Asheville NC, and I am in Texas). She changed the battery before her cross-country drive to visit last weekend... and about the time she returned to Asheville - that darned battery light came on again. And now is pretty much always on - and the car is running rough. If she lets it sit a while - she can start it up again and drive. So - fast forward to this morning - she got a 160Amp alternator from AutoZone, and had a friend of hers install it. She texted that the Liberty was running smooth again.... 2 hours later - I got a call from her - saying it's back on - and running rough again.

So - AZ is going to replace the new alternator - with another new one. If that doesn't fix the problem - what else can I have her diagnose via long distance? Is there a fusible link? Would that cause the power problems and the battery light if it's blown? She had AZ run engine codes earlier in the week, and they told her it was either alternator, or that a load was dropping voltage - to cause the light and rough running. Maybe a new connector that goes into the alternator wiring harness (PCM connector?)

I hate that I'm not there to diagnose quickly, and in-person myself...

Thanks for any direction...
Rex S.

 

[Billwill]

Be careful when replacing Alternators in that they are not all the same...there are differences between years and models ie. gasser or CRDs....the regulation methods do vary between models and years.

The thick wire coming off the RED Battery connector going to the large lug on the Alternator is a Fusible Link ie. it has a fused section within it. The color of the wire also changes depending on what Alternator is being used ie. different colors have different fuse ratings!

Very often the person replacing the Alternator does not first disconnect the battery...the large lug on the Alternator has power on it at all times and touching chassis/engine with the wrench will blow the link! Battery Light will then stay ON and the battery will slowly go flat as you drive along.

You need a Voltmeter to check that you have +12 volts on this large lug with reference to chassis...this should rise to about 16 volts when engine is revved up!

Check the battery Ground cable is clean and tight where it bolts to chassis and check engine grounds...V6 Gasser has two grounds going from back of the heads to the Firewall...CRD ground goes straight to chassis.

 

[jeepop]

I had to replace one of the clamps to my batter too. There was a voltage drop from the clamp to there the wire was crimped in on the factory wire. It could very well be the ground wire at the firewall or at the battery too.

 

[GreenJeep06]

It’s going to be a component in the computer. Check Rockauto for replacement’s they have the best write ups on how to replace these. Also have the best prices. May need to have a dealer reset the chips for mileage.

 

[jeepop]

Maybe but I doubt it. Alternator is not putting out enough juice, or its putting out plenty of juice and there is resistance causing a voltage drop somewhere. There is a reason why there is a full section of battery and ground cables in every autoparts store.

 

[Billwill]

There is always a good chance that it is a wiring problem....I have pulled off about 15 wiring faults after a front end shunt!

Best to download the 2006 KJ Service Manuals here....describes how charging works and the Wiring Section 8W has the Wiring Diagrams!

Page 8W-20-2 shows the "Generator" ie Alternator with the Fusible Link coming in at the top and the control coming in at the small connector pins #1 and #2.

Pin #2 has a Black wire on it that goes onto ground via a few connectors....OP needs a cheap Digital Multimeter to check that this lead is in fact at Ground....no harm in adding a seperate Ground right at the pin #2 of the small connector to see if that helps!

Pin #1 on the small connector for either a Gasser or a CRD is a Brown Wire with a Dark Green stripe...in the case of the CRD it goes to the BCM and in the case of the Gasser it goes to the PCM.
In both cases there are lots of Connectors in place that could need re-plugging due to a dirty contact....the Wiring Diagrams in Section 8W shows where most of the connectors are located.

The OP needs to let us know if the problem has been resolved but here are the 2006 Jeep KJ Service Manuals:

www.colorado4wheel.com/manuals/Jeep/KJ/