Battery light on...time for an alternator

[woodman60]

I've been hearing a whine for the last few days. Pitch rises with RPMs. Thought it was possibly power steering pump and was going to flush fluid, but before I got around to that I had my battery light come on and stay on when starting and during a short drive.

Battery is 12.3 V when engine is not running but drops to 11.9 V at idle. The 7.5 amp alternator fuse is good, and the battery terminals are clean and tight. Also the whine seems to have stopped.

I've looked at a bunch of threads, but want to check in to ask whether there is anything else to check before I pull the alternator? Thanks for the help.

 

[Tanker Yanker]

Definitely sounds like the alternator crapped out. I would humbly suggest while you're at it though to go ahead and treat the Runner to a new battery too. If the battery isn't in great shape, it can reduce the life of that not so fun to change out alternator you just bought! My $0.02.

Winter's coming anyway, and that's usually when a weak battery gives out without notice....again, my $0.02.

 

[Rocnroll]

Testing the Alternator with a Volt Meter

Hey guys...I watched this video [https://youtu.be/LGB6ZEjGm7Q] it has as simple way to measure the alternators function through a voltage loss test for the alternator....

Keep RocnRollin hope this helps

 

[radlynx]

check all rotating pulleys as well while the belt is off. one of your bearings might be causing the noise.

Sent from my SM-G930T using Tapatalk

 

[ZiaMan]

Literally went through the same thing last year - thought it was the ps but ended up being the alt. I have a v8 so I changed the accessory belt at the same time. Depending on how close or far from a timing belt replacement I would change the tensioner and guide bearings as well.

Ps- search my posts for links to how tos

 

[woodman60]

Done.

Fortunately I didn't get stranded this morning when I needed to make a few short trips before I could start on this job. Battery was at 11.5V when I finally started the work.

Alternator was a Toyota part, probably the original since I never saw it on the extensive service records I got with the truck. 195K seems like a good run for an alternator.

This was incredibly easy, and there is a good video online. If you follow that, however, skip the step of removing the idler pulley. Replaced the serpentine belt while I was at it. Pulleys all seemed to move freely so didn't bother with those.

Total job took about 3 hours. The longest time sinks were.

1. getting the dam electrical plug off of the alternator (always use dielectric grease to save the future owner of your rig some time).
2. making two trips to O'Reilly since I forgot my wallet the first time.
3. getting the lower bolt back in the bracket for the wire loom. Very tight for my big hands. Finally left it off after 15 minutes of trying.

Started up...no battery light...charging at 13.7V

I love working on my 4th gen. So easy.

 

[riceandpho]

Done.

Fortunately I didn't get stranded this morning when I needed to make a few short trips before I could start on this job. Battery was at 11.5V when I finally started the work.

Alternator was a Toyota part, probably the original since I never saw it on the extensive service records I got with the truck. 195K seems like a good run for an alternator.

This was incredibly easy, and there is a good video online. If you follow that, however, skip the step of removing the idler pulley. Replaced the serpentine belt while I was at it. Pulleys all seemed to move freely so didn't bother with those.

Total job took about 3 hours. The longest time sinks were.

1. getting the dam electrical plug off of the alternator (always use dielectric grease to save the future owner of your rig some time).
2. making two trips to O'Reilly since I forgot my wallet the first time.
3. getting the lower bolt back in the bracket for the wire loom. Very tight for my big hands. Finally left it off after 15 minutes of trying.

Started up...no battery light...charging at 13.7V

I love working on my 4th gen. So easy.

i hope you put the battery on a charger first. if the battery was that low, you can kill that brand new alternator you just put in. v6 or v8? the v6 is so easy to do.