Battery light (charging system) on, but no obvious issues

Howdy all

I have an '09 base 4x4, 2.7L. Swinging at 160k or so miles.

The other day, I was towing my boat, stalled out a bit on the ramp (forgot to go into 2L), and when I returned home, noticed my battery light (for the charging system?) was on. Note: I did not plug my trailer lights in, as I was on private property the entire time and only had to drive like 2,000 feet. Let it sit overnight to see if it would clear itself. Pulled out my multi-meter the next day and was having no issues, running on idle with my A/C, stereo, lights, and accessories, I was still registering 13.15v. let it sit for 30 mins to see if the battery would drain, still 13.15v when I came back.

I was in need of some routine maintenance anyhow so I brought to my mechanic, but the battery light actually turned off on the drive there (mechanic is only 2 miles away).

Notes from my mechanic:

1. The battery ground was completely corroded off, and some other grounds were loose. He fixed. (but note: light was off at this point)

2. He did a test of the battery and charging system, and he said the battery light turned on again while he was running the test. But the results came back fine, see attached photos of results.

3. My battery is about 8 years old but still testing "OK", probably time to replace.

It's been a couple days since I got back from the mechanic, I've probably driven about 100 miles since then. Battery light is still on, but still no obvious issues.

Mechanic has suggested it probably wouldn't hurt to replace the battery (it's past due), and it's still on it's first alternator. I've replaced my belt before and found I could have easily pulled out the alternator and replaced.

Any suggestions for diagnosing/exploring further? I'm kind of inclined to just replace the battery now, then the alternator when I've got the cash & time to do it (later this summer)...
I'm just kinda concerned because even if nothing is wrong, but the battery light stays on, I won't know if I actually DO have an issue somewhere down the road... sometimes I have to travel for work and a bit concerned about doing so with this light on...

 

The battery light has nothing to do with the battery.
It only comes on with a no charge/low charge condition from the alternator.
Why they use a battery symbol, I don’t know. It’s not an accurate representation of the issue.

See here for description and diagnostic
https://www.tacomaworld.com/threads/2nd-gen-information-diagnostics.784008/#post-28042155

 

thanks, right, i was aware it wasn't directly related to the battery (but again, replacement is way past overdue so might as well swap out anyways)

i'll check the link, thanks.

 

I’d recommend replacing it.
8 years is a long time.

My OE made almost 7 years.
The last one just over 6 years.

I could tell it was cranking slower well before it went out.
But then……I just went out. You really should NOT push them like I do.
But what can I say, I get all the life out of the stuff I buy.

 

Lol, when I bought her used at 80k miles in 2015, it still had it's original 6-year old OEM battery... dealership wouldn't give me any discount or anything when i tried to haggle, so I said "at least give me another OEM battery".... and that's the 8 year old one i'm going to replace

 

The next one I buy will be an OE.
After it was all said and done, I paid just over $200 for an after market 3 year warranty battery.
And I had to put it in myself.

Last time I was at the dealership, they had their for just a little more.
Like $230 installed. And every time I have been to the dealership (recalls and TSB) they always inspect the truck. So I get a free inspection and free battery installation. Sign me up…….

I’m not afraid to let someone else touch my truck.

 

If you have a local electrical shop, they can test your alternator on the vehicle (at the alternator, not the battery) and if it needs attention, rebuild it for you.

My experience has been that the cost to do this was around the same as buying a parts house pig in a poke and doing the work myself.

Just something to consider.

 

Try a computer scan (trouble scan).

 

We have a shop in town that does just that.
Been in business for decades.

They will rebuild it as good as new and sometimes better.
The problem is, they are always overloaded. If you can’t wait a week, then they aren’t the place to go.
But they can do just about every, if you have an old tractor, or head equipment, they can save you a lot of money.

 

My buddy has exact same truck and a spare alternator lying around he bought but wound up not needing, so we're just going to throw it in just for the fuck of it. Easy enough to take the belt off and put in.

first of all, nice user name, a maineah myself (in midcoast) -- there's no check engine light so nothing to scan?

 

FYI, I hope this doesn’t happen to you, but not using an oem alternator might cause charging issues. Rockauto sells Denso remans which would work “if” you get one that works or is not damaged.