I have an 02 Taurus and my dash battery light has come on twice in the past week. Once after a few miles of driving, seemingly random, and once when I was warming the engine up. It's been 20-30F around here lately. This second time, I started the engine in the morning at about 20 deg F. Let the idle come down to normal and after about a minute I gave a little gas to get the engine up to 1500 rpm, which is when the batt light came on. It switched back off after about 5 seconds, after I got off the gas.

After sitting for 6 hours, my old multimeter shows 12.48 V on the battery. It's one of those 2 year warranty EverStart batts from Walmart, manufactured in 3/23, so still in warranty.

Does a 12.49 resting voltage justify a warranty claim, assuming it's not the alternator that's going bad?

Thanks

 

OK button not clickable because Engine is not selected. Do you know it's DOHC or OHV?

Try this, insert your key and turn it to ON/RUN position, the battery light stays on continuously or proves out (goes away) in a few seconds? Or it turns off shortly after starting?
When the light stays on when driving, it means there is a problem with the charging system. Alternator doesn't fail easily usually it can be the voltage regulator, the brushes, or the wiring problem between that and your battery. The brushes can last as short as 5 years, a short lifespan, the worn out part, because of metal to metal contact to the commutator of the alternator. Say a new brush is 2-inch long, it can be shorten down to 1/2-inch over time but when it's 1-inch left it should be replaced already. Anyhow, do NOT throw any part at your car yet.
Additionally, how is the cranking, is it slow? Check what voltage you get during cranking:
1) put your voltmeter red to battery positive black to negative, check what voltage you get and remember that
2) find a helper to crank, and what voltage you get during cranking?

 

Thanks for the info Heiko. I have the OHV, the third engine option above.

Other than the two times the dash batt light has come on the lights acted normal. Comes on when you first turn the key and goes off fairly soon after.

Cranking seems to be full speed, even in this cold.

I've done some more testing. Multimeter with the engine running shows 14.74 V, and with engine running, high beams and high fan on shows 14.47 V.

Not sure what voltage I'm getting when cranking but I'll try to test that out soon.

I just wonder how much these low outside temps are effecting things here.

 

Pinpoint-D.pdf attached below.





Since that happened to you just a couple times, that might just be an early sign to alert you to get your attention. What I would do is to do the cleaning on the electrical connectors using contact cleaner or 91% isopropyl alcohol and see if that comes back the 3rd time, then take further action accordingly. If you want and have the time you can go over the test above as well as pinpoint D.

 

Hi Bradley,

If the spirit so moves you,,,,,,,,,,,,,, it might be a good idea to check the plug that plugs onto the alternator. If poor contact there due to loose internal connections, can produce that type problem you are seeing with your vehicle.

 

Whether you are re-tightening or cleaning, don't forget to disconnect the battery negative cable first. Torque specs shown above just in case you need to remove the alternator, you probably don't have to. And your voltage regulator is internal and not replaceable standalone.