Battery Light is ON -- now what ??
 

I started driving home from work today and about 15 miles from home my Red Battery light on the Dash lit. I got home and started the truck 2 or three times after having the doors open for a while. No problems with lights or radio etc...

Anyone know if that means my Alternator is about to go ? I'm thinkingof bringing the truck to Autozone to have them check the Alternator. If I need one they have a Gold Duralast lifetime warranty one in stock.

Anyone have any advice :

1 - Sounds like alternator most likely ? I got a new Deka Battery less than 12 months ago and never had it go down.
2 - Is Gold Duralast any good ?
3 - How hard is it to DIY replace ?


Thanks !!

-- I get to add this to my a/c blowing out of defrost that I still haven't got to fix list ! lol

Offhand it does sound like a charging issue. Do you have a multimeter lying around the house? If so you can do a quick check by first checking the battery voltage with the engine off ( somewhere around 11.80 or so if I remember correctly ). Then recheck with the vehicle running and it should be somewhere near 14v or so.

Edit: I would first make sure that your connections are clean and tight since you mentioned a new battery in the last year or so.

If it turns out to be the ALT, it's easy to replace with only a few tools. Get a replacement ALT with a lifetime warranty.

Everything you need is in this post: https://www.ford-trucks.com/forums/9...lternator.html

Keep an eye on your battery. Chances are, it wasn't getting a good charge from your dying alternator.

UPDATE --

Had a VERY BUSY weekend with daughters birthday and more stuff - but I got a few minutes to do a little work.

Tightened the battery cables ( the negative was just a tad loose - so i retightened it ).

Then I took it around town for a while. The battery light stays lit , but when driving it uphill and trying to hold 2,500 - 3000 rpm the lights flickers off now ( instead of solid lit ) and after about 20 seconds of driving it at 3k rpms it finally goes off completely. The battery stays off for a few minutes but then returns after coasting around or not hitting that high an rpm for such a sustained period of time.

I also tested the battery with the engine running and shows about 11.x volts, best i could tell without finding the good digital readout voltmeter. Giving it gas to 3,000 rpms while in park still does not cause the battery reading to fluctuate...

Still sounds like the alternator may not be putting enough ? Should I put in a new alternator ? I'm looking at an Durastar Gold from autozone if I need one.

I would say take it to a local parts like autozone and such, they can test your ALT, cause it sounds like it is going out!

Agreed, the voltage does seem very low with the engine running. It is also possible that the battery is now pretty well taxed if both the alternator was failing and you had a weak connection.

Best to run it to the local auto and have them test them both really quick.

Replace the alternator.

Duralast Gold alternators haven't given me a problem on the cars I've installed them on.

I definitely sounds like the alternator is going. The voltage should be around 14.5 all the time, regardless of engine speed.

A dead cell in the battery can cause that too...but then you would have starting issues. So, I would think it is the alternator. It can be tested at any parts store.

Picked up a new Duralast Gold 130amp alternator at Autozone last night. Before heading out to work this morning I popped the hood and pulled the old one. Pretty straight forward - luckily nothing was seized or rusted through.

Drove to work and back about 45 miles roundtrip and no longer have any battery light. Looks like we're all good :)

Thanks again guys for all your help !

So now that his issue has been solved... hope you all can help me. My red battery light comes on randomly while driving.

The batteries are less than a year old and were tested last month (good). I checked to make sure the battery cables are tight...

I just replaced my alternator (thanks ED) with a Ford Remanufactured one. When the light came on I had 14.3 volts driving down the interstate. The light went off and on randomly during my 3 hr trip. During idle now with the light off I am getting 13.6 volts and 12.5 with the engine off... my red battery light comes on randomly while driving and stays on for a while and then turns off randomly.

Ideas?

Check your body ground.

Stewart

I think I know what you mean (the ground cable that goes from the passenger battery to the body fender)... but can you elaborate on location/plural? :-huh

Yeah, to ground from the battery to the body.

Also, make sure your terminals and clamps are clean and "fresh". I use Noalox compound between the terminal post and clamps to protect the metal and enhance conductivity. Noalox Anti-Oxidant Compound

I'd also make sure your cables are all up to spec and in good working order. Make sure the connection where the clamps attach to the cable wires are in good order.

Stewart

Drove around some more yesterday:
Watched the volts move based on RPM. If there were no electrical accessories on, at idle the volts would be 13.9. But the second you turn on the AC or fan the volts drop to 12.5 at idle. If you drive and get the RPM up above 1000 the volts would increase to 13.6.


Is it normal to see the volts vary with RMP and accessory usage so much?
I remember that when I installed the alternator at first the volts would be a healthy 14.5... but cant get that high now.