4.7 Alternator not charging help PLZ! Need ideas.

swapmeet

swapmeet

New member
I'm experiencing something strange. Hoping someone can help ID the issue.

Currently:
Go wheeling for 6+ Hours today, (mud, water crossings etc) I experience no problems (watching very closely)
Towards the end of the day, battery light comes on. Alternator isn't charging.
Take to coin wash, spray off the alt/ engine, no help.
Drive home, hose wash, let it cool off etc, same issue exists.
I have an AGM battery (thankfully), after letting the truck sit, it shows 12.06v resting and 11.8 running (at the battery posts).
It's a Factory Denso ALT.

Previous:
Last time I went wheeling the same problem happened. I drove home, washed engine, pulled the ALT off, had it tested, it was fine. Put it back on everything is good since then. (month-ish)

So what have I done differently besides taking it off and re-installing it? That's a lot of work btw so i'd rather not do it "just because."

This is my daily so not having a ride tomorrow really sucks. Any suggestion is welcome.
 
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Id say alternator is bad. If you have a big dog battery and a short commute to work, you could probably just charge the battery overnight and drive to work and home tomorrow. Leave all the accessories you can afford to off.
 
Thanks for responding ya'll. I wasn't sure how many responses, if any I would wake up to this morning.

I talked to a buddy who is a Ultra Certified Master Toyota Tech (seriously though, he's been wrenching for Toyota longer than i've been driving)

He agreed that "typically" Toyota Alternators don't go bad. It's just not normal.

Obviously the change in circumstances that I introduced is water. Muddy water.
I was laying in bed thinking about what I did last time that might have fixed it and his thoughts went in the same direction.

In order to pull the alternator out, you have to unplug the little 3 wire plug from the side or back. One of those wires tells the alternator to turn on. More than likely, water has worked its way into that plug and has created a short which makes it think it's not supposed to be running.

My plan this afternoon is to pull my skid and try to get that wire off without pulling the entire alternator. It could be tough but thats the plan. I'll use compressed air to dry the plug and the alternator, probably pack the plug with dielectric grease and maybe try to seal up the entire pigtail from the plug back.

This is all obviously on a hunch. But It's a plan, and sometimes it just helps to have a plan.
 
I just recently had charging issues also. For me it ended up being a 15A IGN1 fuse in the fuse box in the cabin. Took me a new alternator and battery to figure that out.
 
hondarcb said:
I just recently had charging issues also. For me it ended up being a 15A IGN1 fuse in the fuse box in the cabin. Took me a new alternator and battery to figure that out.
Click to expand...

I saw your thread/ post and checked that last night. My fuse is intact, for better or for worse. Good info though.
 
anyone remember the thread about putting in the 200A Supra Alternator?
__________________
2007 SE V6 Titanium
 
Well, none of my attempts to make it work have succeeded. So i'm researching replacements.

SWEET BABY JESUS new factory alternators are $600!!!!

Its so crazy... there are Reman units from O'rileys for less than $200 and OEM for $600. I don't get it .
 
Got my alternator out last night. [MENTION=77155]bergs[/MENTION] maybe it fits through the fender on a V6 but short of removing the power steering bracket, I don't see it coming out on a V8. I pulled my skid plate (which had half a inch of mud standing in it) and dropped it out the bottom.

I'm taking it in to get tested this morning, although even if it works I don't think i'm going to put it back in. My Toyota Tech buddy gave me the schematic for the 3 wire plug on the back and all the wires measure as they should.

I have a line on a used OEM alternator locally so i'll try to get that today and see if it remedies my problem.
 
Well, good news... I guess?

My alternator is bad! Puts out 11~ish volts.

At least I have a defintive "its not working" condition, vs the a month ago where "its broken... oh wait, it works." heh...
 
If you're not keen on having a reman alternator from O'reallys permanently, spend the $200 on the reman, install it, and send out your Denso to an alternator shop to be rebuilt. Swap it back and return the reman or keep for a trail spare.
 
chitown40 said:
If you're not keen on having a reman alternator from O'reallys permanently, spend the $200 on the reman, install it, and send out your Denso to an alternator shop to be rebuilt. Swap it back and return the reman or keep for a trail spare.
Click to expand...

I may do something similar. I'm getting a take off from a national salvage yard chain. Only has 20k/ mi on it. So that "should" be a New, not rebuilt unit. Which I trust more than a reman. Even a Denso Reman.

So the plan now is to get the 20k Alternator on, and either rebuild mine myself or take it somewhere and have it rebuilt and maybe i'll sell it. My factory one lasted 122k, I don't see that being a likely trail spare candidate.
 
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