Battery light 4th gen 4R

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Montijo505

Montijo505

Joined
Jul 25, 2019
Threads
6
Messages
285
Location
Rio Rancho, New Mexico
Got the red battery light couple days ago. Tested battery (new from Costco) reads about 12.3 engine off. Tested with engine running and it’s 11.8-11.7. Took negative cable off it stalls.

Replaced alternator brushes, same scenario. Do I just replace the alternator? Tested the diodes too with multimeter and they read good.

Ordered a Denso alternator from Rock auto (cheapest). Hopefully that fixes it.
 
Could possibly be a blown fusible link.
 
Mauser said:
Could possibly be a blown fusible link.
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When I test the alternator with engine running it shows 11.7-11.8, I think if it was the fusible link the alternator would still read above 13 yeah?

Anyone know how to get a multimeter on the prongs of the fusible? Looks like they’re hard to access from a quick search. Visually it looks fine, not melted or blackened or anything I can tell.
 
Montijo505 said:
When I test the alternator with engine running it shows 11.7-11.8, I think if it was the fusible link the alternator would still read above 13 yeah?

Anyone know how to get a multimeter on the prongs of the fusible? Looks like they’re hard to access from a quick search. Visually it looks fine, not melted or blackened or anything I can tell.
Click to expand...

I think that depends on where you measure from. It is probably a bad alternator. I don't ever screw with them. I just replace them.
 
Denso alternator fixed it. No clue what was wrong with the one I changed the brushes on. New one did make a horrible squealing sound for like the first 10-20 seconds and then shut up. Battery light was off as soon as it turned over.
 
take the old alternator to the Start Shop and have them rebuild it then toss it on the shelf as a spare. Probably the rectifier in it took a crapper.
 
alia176 said:
take the old alternator to the Start Shop and have them rebuild it then toss it on the shelf as a spare. Probably the rectifier in it took a crapper.
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Yes, I agree. Start your hoarding career today. You can never have enough spare junk in the garage. As one fella here once said "never throw anything away."
 
Good advice guys, I think I will have it rebuilt. Average cost?

Any idea why the new one squealed and smelt burnt for a few seconds before going silent and operating normally?

Battery engine off now reads 12.75, before was 12.1-12.3. Alternator at the post reads 13.8ish, same at the battery terminals with engine running.
 
Did your battery have a full charge when you first started the truck?

I don't screw around with rebuilding. Out of all the alternators that I have replaced with a parts house alternator I have only had one that didn't last a year. They usually have a lifetime warrantee.

Rebuilders only replace the parts that are bad in an alternator, same as the crappy parts house ones.
 
Mauser said:
Did your battery have a full charge when you first started the truck?

I don't screw around with rebuilding. Out of all the alternators that I have replaced with a parts house alternator I have only had one that didn't last a year. They usually have a lifetime warrantee.

Rebuilders only replace the parts that are bad in an alternator, same as the crappy parts house ones.
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Yeah it’s a new battery. Bought in like December? The light turned on while driving. Car was acting normally. I drove it for about 30 minutes with the light on so I assume that’s why it was reading a bit low before I put the new alternator in.
 
Montijo505 said:
Yeah it’s a new battery. Bought in like December? The light turned on while driving. Car was acting normally. I drove it for about 30 minutes with the light on so I assume that’s why it was reading a bit low before I put the new alternator in.
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If the battery isn't completely topped off it stresses a new alternator and a lot of times they will scream. Way back when I was working on heavy trucks we wouldn't warantee an alternator if we didn't fully charge and load test the batteries.
 
Mauser said:
If the battery isn't completely topped off it stresses a new alternator and a lot of times they will scream. Way back when I was working on heavy trucks we wouldn't warantee an alternator if we didn't fully charge and load test the batteries.
Click to expand...
Ah gotcha, didn’t think of that. Battery was showing like 12.3 before start up.
 
Mauser said:
Rebuilders only replace the parts that are bad in an alternator, same as the crappy parts house ones.
Click to expand...
This seems to be standard operating procedure with engines too! In general, good replacement components are still available. If you track down good parts you can fix it yourself.
alternator1.webp

Cleaning is the most troublesome part.
 
nab856 said:
This seems to be standard operating procedure with engines too! In general, good replacement components are still available. If you track down good parts you can fix it yourself.

Cleaning is the most troublesome part.
Click to expand...

Do you have a source for buying non Chinese rectifiers and bearings? The brushes aren't a big deal to me.
 
alia176 said:
Do you have a source for buying non Chinese rectifiers and bearings? The brushes aren't a big deal to me.
Click to expand...
Start with IATF 16949.
 
alia176 said:
take the old alternator to the Start Shop and have them rebuild it then toss it on the shelf as a spare. Probably the rectifier in it took a crapper.
Click to expand...
Negatory ghost rider...Start shop was sold (?) a number of years ago and they rebuilt with junk components now. The last 2 alternators I had rebuilt there did not last and the last one for the 2011 4R came back worse than when I dropped it off. (I solved the issue with a new Toyota alt and several new batteries)

Ali, remember the last Ouray I made several years ago and I was shore charging the battery every night to make it through the day!?
 
lurch said:
Negatory ghost rider...Start shop was sold (?) a number of years ago and they rebuilt with junk components now.
Click to expand...

Well, that sucks. There was another place we used for alternator and starter rebuilds when I was at the City. TNT Distributing. I'm not sure what their status is. They don't have too many recent Google reviews, but the reviews are good.
 
lurch said:
Negatory ghost rider...Start shop was sold (?) a number of years ago and they rebuilt with junk components now. The last 2 alternators I had rebuilt there did not last and the last one for the 2011 4R came back worse than when I dropped it off. (I solved the issue with a new Toyota alt and several new batteries)

Ali, remember the last Ouray I made several years ago and I was shore charging the battery every night to make it through the day!?
Click to expand...

I called them to find out where do they get their parts from. It's from here: https://www.waiglobal.com/ So, this is garbage parts apparently.

Like Jon said, we may not have any other rebuilders in abq, but if we can source quality parts, we can rebuild these things ourselves.
 
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