2005 Tundra Battery Light keeps coming on

[northestPM]

Hi all. My 2005 Tundra 4.7L with 350k had the battery light come on a couple times recently. First was a couple weeks ago, then again last night. The light comes on, wipers are really slow when this happens.

When I started it this morning, no battery light. Drove in the rain for a bit, parked the truck. Started the truck again and the battery light was on. The windshield wipers were really slow moving. There was clearly a problem with a lack of power/juice.

Is this an alternator issue or maybe a corroded alt to battery wire? I just replaced the battery a few months ago.

 

[eljefino]

Well it could be either but with your mileage I bet the alternator brushes are worn out and making intermittent contact.

 

[drtyler]

Alternator definitely needs to be checked.

Make sure battery cable ends & clamps are in good shape. I've seen some excessively corroded Toyota battery cable ends & clamps.

 

[AandPDan]

Is it the original alternator? I'll second it could be worn brushes.

 

[JeffKeryk]

Start by cleaning your battery and battery posts. Then go buy an alternator. I generally like the NAPA remans, about $120 I think. Good luck.

A volt ohm meter is a handy tool...

 

[joegreen]

Repair the oem alternator with new brushes instead of buying a cheap Autozone unit or the like. The oem unit will be more reliable.

 

[gman2304]

The slow wipers are telling you something! I just preemptively replaced the original alternator on my 2005 Chevy 5.3 with 244,000 miles with a new, not rebuilt AC/Delco Gold 145 amp from Rockauto. $160.00 delivered free to my door with no core charge and about as inexpensive as a reman from O’Reilly’s. The original was charging fine and I’ll keep it as a backup but after 18 years, I just felt it was time.

 

[Kira]

Also remove the battery from the vehicle and fully charge it. You may have injured it gravely.

 

[fantastic]

Sounds like the classic symptoms of an alternator going out. Time to replace it & at your mileage on this truck it would be fine if you went with a re-manufactured alternator.

 

[Paco Pena]

I would also take the opportunity to make sure all your grounds are clean and tight. Any electrical issues with an older vehicle I do that before digging into it.

Paco

 

[meep]

The light either functions by coming on when the voltage is low, or when the alternator isn’t sending anything out. The end result is the same, just one method alerts you to a problem earlier than the other.

agree - replace/repair alternator, and put the battery on a charger overnight until you get it worked out.

 

[IndigoInkTaco]

Not sure about Tundras, but Toyota is not selling new alternators any more and only reman'd. But I'd also tend to agree the alternator is the likely culprit. See if you can test the charging system.
I'm going through this same process and just bought new cables to make all new battery cable wires. I'm only at 210k miles though.

 

[wtd]

Get a multimeter and check your charging voltage while the truck is running. I would check it at the stud on the back of the alternator and at the battery.