[fvlewg65]

I’m trying to help a lady from work with her 2015 4Runner Limited. I’ve read through multiple posts and I still can’t figure it out.

Last February her battery died and was replaced, everything was running fine and then in June the Battery light on the dash came on. She had her ex-father-in-law look at it and he’s said the alternator is charging the battery and not to worry about it.

She asked my opinion so I said I’d have a look. This is what I’ve done:

OBDii code reader - no significant codes, check engine light wasn’t even on

Tested the battery - seems fine, 12.78 at rest, drops slightly under load then recovers. Rated at 930 CA, battery analyzer said 873 CA. Battery connections are nice and clean, no corrosion.

Tested the alternator - charging fine but removed it and took it to a starter and alternator repair shop, they said it checked out on their test equipment but said maybe there was something internal that they couldn’t detect with the voltage regulator. So I replaced it with a brand new one. Inspected the wiring from the alternator.

Tested the charging system - 10.85 cranking volts, 14.21 alt idle volts, 14.13 alt load volts

Checked the #22, 7.5 amp fuse in engine bay

Checked the ground wires.

Battery light is still illuminated on the dash.

I am flummoxed! I have no idea what to check/next or what the problem is. I’d hate tell her to go to the dealership because I can’t figure it out. Any advise would be greatly appreciated. Thanks in advance.

[fkheath]

Since all of your voltages tests appear to be normal, and the tests by the shops have show that everything is working correctly, it is understandable that you are perplexed. I would be too..

Perhaps your best approach would be to get a good understanding of the charging circuitry in the 4Runner. The "battery" light in cars is really turned on by the voltage regulator circuitry and has nothing to do with the battery it's self. Perhaps looking trough the diagnostic steps in the 4Runner repair manual would help: TOYOTA 2016-2019 4Runner Repair Manual RM27F0U