Battery light coming on 02 SR5

Battery light coming on randomly. Obviously a low charging signal. Had the battery and alternator checked and alternator was reading 14 with nothing on and 13.4 with lights,radio,and A/C all turned on. Battery check detected the cranking amps was around 500 and needed replaced-it was 6 years old. New battery yesterday evening and battery light back on today. Is it possible the alternator could be failing on occasion?

Not a mechanic by no means which is why I have owned Toyota's since 1984. But this is my 02 with 401k and it is most certainly due some issues. The only thing that has been a major repair is the original clutch finally had to be replaced at 400k. This is the original alternator by the way.

 

The alternator controls the light by grounding the L terminal, the only things that will turn the light on are an alternator problem, a short to ground on the wire going to the light, or a problem in the cluster.

 

With 400K, I'd say it's the alternator going out. It's giving you a warning for a reason

 

Thanks Dm93 & six5creed.

 

My '03 did the same thing at 201K. I replaced the battery first and the light came on shortly after again. It would come and go while driving, replaced the alternator and it fixed it.

 

Lets not rule out the simple a loose belt!

I know I don`t ever think of that because it is a unconscious first check.

many reman alternators bought because of a loose belt.

 

Great info. I will check that for sure. Thanks Bivouac

 

With that high mileage, the brushes in the alternator are likely worn out and loosing contact. A fairly simple and inexpensive fix.

https://www.tacomaworld.com/threads/replacing-alternator-brushes.564805/

 

When I said alternator problem I meant a problem relating to the alternator (loose belt, bad wiring connection, bad alternator, etc) not that hey the light's on replace the alternator.

 

Coming from you that is a given!! Test before

Then new brushes at 400,000 miles would be a good idea.

I keep being told that simple job is beyond most people here go figure.

 

I hear that, testing seems to be a last resort rather than a first step for many people.
Schooling someone on how to test properly is a whole nother topic

 

Ha Ha Ha in most cases Mission Impossible!

 

I still try my best
What's really unfortunate is it's the same way in over half the shops out there too, replace all the parts first then either test or ship it elsewhere.

 

Update: Replaced alternator and have been driving for a couple days and no battery indicator light coming on yet. Looks to be solved so far. Did discover when replacing the alternator that the nut on the bottom bolt had backed off and was gone and the bolt had backed out about a half inch. No idea when that happened but the belt was not loose and the alignment was still good on the old one. Note to self- check alternator bolt when servicing going forward. Thanks for all the info from everyone that replied to my post.

 

Glad it was a easy fix !

Since Mom and Pop automotive electric shops are vanishing all the time . The quality of rebuilds has gone downhill .

 

Yea everything is junk anymore, quality is a thing of the past. Nowdays it's all about mass production and how cheaply it can be made.

 

I have had good luck with remanufactured Denso through my Toyota Dealer the core charge is low enough to eat .

Then I can rebuild as spares like anything once you learn it is a easy job.