2002 Limited Charging System Issue

I own a 2002 Jeep Liberty Limited and am having a heck of a time diagnosing a charging system issue. Seems like one piece of the puzzle leads to another. I love my Libby and want to keep it a while longer, but this is driving me crazy.

Symptoms--

• Battery light on dash on currently
• No check engine light
• No faults on ODBII reader
• Voltage on battery 12.55 when ignition off
• Voltage on battery 11.65 when engine running

Things done so far

• New battery
• New radiator cooling fan relay
• New battery temperature sensor
• Alternator checked at O'Reilly and AutoZone and alternator shop
• Checked fusible link between alternator and battery

Dealer wants to charge me $145 just to test the PCM and give a diagnosis.

I've read more comments on forums that I could possibly digest. I've deduced it has to be the voltage regulator, hence I am suspecting the PCM needs to be replaced.

I am more than willing to replace the PCM if needed, but so far I cannot find a reputable vendor on-line. All of the one's I have spoken to have HORRIBLE ratings from consumers.

Right now the Liberty is sitting in the driveway and I am commuting on my motorcycle. So getting to and from work is working.

Any and all suggestions are very much welcome. If you know of a good auto electrical expert in Houston I'm open to hearing about that. And if you have a recommendation on a source for a PCM that is welcome as well.

Thanks ahead of time.

Darrell

I would replace the PCM only as a last resort.
It's not an uncommon issue, they make an external regulator kit: ERCKFRM Combo - Heavy Duty Chrysler, Dodge, Jeep External Voltage Regulator Kit with Field Replacement Module

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Are you sure the alternator is still okay? I thought the load tests at the parts shops don't work perfectly on our jeeps. I recently swapped my alternator (brand new nippondenso 136 amp for $84 shipped) and all is well....

Have you used a multimeter on the positive terminal on the alternator (and negative on chassis) while the engine is running?

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You could by a ford extra heavy duty voltage regulator like me and give it a try.
here are the steps
If you do decide to by a new ECM you may create new issues that you do not have rite now like engine problems.
first thing you will need is a spare alternator connector, I got mine from a junk yard.
here is a link for that
http://shop.advanceautoparts.com/p/...utm_campaign=27795&utm_content=120917&irgwc=1
Next you will need the voltage regulator connector.
http://shop.advanceautoparts.com/p/...utm_campaign=27795&utm_content=120917&irgwc=1
You will also need to get the voltage regulator.
http://www.ebay.com/itm/FORD-Extern...m3604de0434:m:mrIDXh1IYFoAQfWU_Qbg0Sg&vxp=mtr
Next you will want to run a ground from the alternator to the case of the voltage regulator.
Next run a wire from a switch ignition source like the radio to the terminal labeled I.
Next run a wire from the alternator positive lug to the terminal labeled A.
Next run a wire from the Black/white colored wire on the alternator connector to Ground.
Next run a wire from the Dark Green colored wire on the alternator connector to the terminal labeled F.
As a side not you will not need to use the Terminal labeled S.
Also note that you will have the battery light on, but there is a part called a field replacement module for that.
http://store.alternatorparts.com/frm-field-replacement-module.aspx
Also note that this is for a FORD voltage regulator not a Chrysler voltage regulator.
These are the steps to install a external voltage regulator, but I would use the extra heavy duty voltage regulator like the ones I found on ebay.
http://www.ebay.com/itm/FORD-Extern...m3604de0434:m:mrIDXh1IYFoAQfWU_Qbg0Sg&vxp=mtr
the part number for the extra heavy duty is transpo F540XHD
The full tread is http://www.jeepkj.com/forum/f202/external-regulator-59831/

Feel free to send me a PM if you have any more questions about hooking it up.

Voltage regulator, integral to the PCM. That's my thought as well.

You've been provided some very excellent options in the previous posts.. I would absolutely go one of those routes before I EVER replaced a PCM, especially in a Chrysler vehicle...