Issue:
Driving slow (~10 mph through road construction) at night, with A/C & headlights/fogs on, the battery light briefly came on and dings once. There's been about 250 miles put on since, with no lights. Jeep runs fine, it has 100K miles on it.

I, regretfully, did not attempt to pull the code...

Here's what I've done since:
1) Checked and both the battery and alternator have excellent connections. Tight with no corrosion.
2) I pulled the alternator and battery had them checked at local, reputable Carquest store. Both are "good".
3) Belt does not look glazed. It's a top of the line Gates belt with ~22K miles.
4) Both the idler and belt tension pulleys spin free, not loose.
5) Belt tension pulley spring has plenty of torque tension.

It's possible that the alternator is "intermittently bad"… and just checked good this morning.

Any recommendations?

Not on my Jeep, but on the wife's Stratus it did the same thing. Random/intermittent battery light with ding. Progressively got worse until finally the alternator immolated itself. My suggestion... find a volt meter that plugs into the cig lighter and see if you spot anything. That's how I finally determined it was on the way out. Voltage would run sub 12v when the ding/light happened, but would return to normal suddenly at some random point.

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2007 Jeep Liberty Sport 4x4 3.7L 6spd

• MOABs with Goodyear Wrangler All-Terrain Adventure With Kevlar 245/70R16
• JBA UCA 4.5
• OME 790/948/90009/N32
• Western Suburbanite 7'4" plow
• DetoursUSA Backbone
• HF 12k# winch

[SIZE="1"]WTB: project liberty near N.NJ. stick shift, 4x4, working motor optional, CHEAP[/SIZE]

Thanks for the reply Sota. I'll check on the voltmeter. I did buy a Actron Code Reader. I had an "intermittently bad" alternator several years ago on a Ford product. Time will tell I guess...

There are a handful of auto techs on this forum, myself included, that could help you. Diagnosing a car over the internet might even be worse than doing so over the phone however. If you can measure your battery voltage running, that would be a good place to start. a passable DC voltmeter can be had for less than ten bucks. Get one.

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2006 Sport 4X4, Deep Beryl Green, NSG370, NV241J, Lifted with OME 927/948 and Bilstein, JBA 4.5 UCA's, Custom 3" Rear Y-Link Extension and Swaybar Relocation, 265/75-16 Toyo Open Country AT2 tires, Black Plastidipped bumpers, flares, and doors, Pioneer speakers, Alpine head unit, 1200w Phoenix Gold Amp, 12" Dayton Reference sub.