Urgent issue- potentially? Battery light (1 Viewer)

[BrianY]

I’m 700 miles into a road trip, now out on Cape Breton Island. I have a battery light that came on this morning and is still on. I put in a new battery before I left.

The Volt meter on dash looks ok with key on Acc and with car running. Is alternator failing? Is it potentially a critical issue, or something I can live with for a bit?

 

[Bisho]

Check the cables are tight, given you just changed the battery. You can’t live with this for long if the battery isn’t charging.

 

[BrianY]

Check the cables are tight, given you just changed the battery. You can’t live with this for long if the battery isn’t charging.

I replaced the positive terminal because it was quite loose. The negative is tight, but I can wiggle it and it moves. Would that cause the light to come on?

 

[Bisho]

Likely not. Best would be to check your alternator, if you have a volt meter handy.

 

[nissanh]

A loose battery terminal could fry the rectifier inside the alternator.

What is the voltage you see at the battery post when engine is running?

If you decide to get a reman alternator, save your OEm. Nothing comes close to OEM. When you come home, get it fixed and install it.

 

[tmoore41]

Similar issues. I am 90 percent sure I need an alternator but since I am new to 100 series figured I would double-check on MUD before changing. Here is story -

Picked up a 2001 LX470 about a month ago. Already put about 4K miles on it with zero issues. I go out of town and my wife drives it (while her 4runner was in the body shop). Of course the day I leave she calls me and tells me the battery light is on. She was nearby the local Toyota dealer so I had her swing in for a quick check. Battery light went off before she made it in. They cleaned the terminals and checked for any codes. All checked fine. About 30 min later all dash lights started to come on. She turned engine off and it would not restart. Got my brother to come jump start. She made it home but he had to jump it a few times to make it. Fortunately my 80 series was running fine so she drove it until I got home a week later. Charged battery for about 30 min with jumper cables from my truck. Started up but battery light still on. Charged battery over night. Checked the battery (two years old) and it seemed fine. Brought a new battery home from work just to confirm. Same issue. Only reading about 12.5V when running with either battery. The wires seem to be OK. Fuses at + terminal check out fine. Belt seems fine (actually looks new). My cheapo code reader does not show any codes. This rig apparently set for a long time before I bought it as there are quite a few mud dobbber nests in the engine bay lol. Other than that it appears that the PO took very good care of the vehicle. 156K miles and no rust. Should I move forward with changing the alternator or is there anything else I should look at first? I have read on other posts about the voltage regulator but I am not familiar with testing. Seems that maybe high voltage would be problem if it is regulator. Maybe a ground wire somewhere?. Thanks for any help.

Two other things - volt meter does show minimal increase in voltage when increasing RPMs. She mentioned that the battery light turned on and off when hitting
bumps. This would lead me to think loose wiring but I cannot find any.

 

[suprarx7nut]

Similar issues. I am 90 percent sure I need an alternator but since I am new to 100 series figured I would double-check on MUD before changing. Here is story -

Picked up a 2001 LX470 about a month ago. Already put about 4K miles on it with zero issues. I go out of town and my wife drives it (while her 4runner was in the body shop). Of course the day I leave she calls me and tells me the battery light is on. She was nearby the local Toyota dealer so I had her swing in for a quick check. Battery light went off before she made it in. They cleaned the terminals and checked for any codes. All checked fine. About 30 min later all dash lights started to come on. She turned engine off and it would not restart. Got my brother to come jump start. She made it home but he had to jump it a few times to make it. Fortunately my 80 series was running fine so she drove it until I got home a week later. Charged battery for about 30 min with jumper cables from my truck. Started up but battery light still on. Charged battery over night. Checked the battery (two years old) and it seemed fine. Brought a new battery home from work just to confirm. Same issue. Only reading about 12.5V when running with either battery. The wires seem to be OK. Fuses at + terminal check out fine. Belt seems fine (actually looks new). My cheapo code reader does not show any codes. This rig apparently set for a long time before I bought it as there are quite a few mud dobbber nests in the engine bay lol. Other than that it appears that the PO took very good care of the vehicle. 156K miles and no rust. Should I move forward with changing the alternator or is there anything else I should look at first? I have read on other posts about the voltage regulator but I am not familiar with testing. Seems that maybe high voltage would be problem if it is regulator. Maybe a ground wire somewhere?. Thanks for any help.

Two other things - volt meter does show minimal increase in voltage when increasing RPMs. She mentioned that the battery light turned on and off when hitting
bumps. This would lead me to think loose wiring but I cannot find any.

If you've checked basic wiring and terminals, I'd move onto replacing the alternator. That battery light is, in essence, the charging light. You can have a perfect battery, but if the alternator isn't charging, that light will come on.

 

[2001LC]

Similar issues. I am 90 percent sure I need an alternator but since I am new to 100 series figured I would double-check on MUD before changing. Here is story -

Picked up a 2001 LX470 about a month ago. Already put about 4K miles on it with zero issues. I go out of town and my wife drives it (while her 4runner was in the body shop). Of course the day I leave she calls me and tells me the battery light is on. She was nearby the local Toyota dealer so I had her swing in for a quick check. Battery light went off before she made it in. They cleaned the terminals and checked for any codes. All checked fine. About 30 min later all dash lights started to come on. She turned engine off and it would not restart. Got my brother to come jump start. She made it home but he had to jump it a few times to make it. Fortunately my 80 series was running fine so she drove it until I got home a week later. Charged battery for about 30 min with jumper cables from my truck. Started up but battery light still on. Charged battery over night. Checked the battery (two years old) and it seemed fine. Brought a new battery home from work just to confirm. Same issue. Only reading about 12.5V when running with either battery. The wires seem to be OK. Fuses at + terminal check out fine. Belt seems fine (actually looks new). My cheapo code reader does not show any codes. This rig apparently set for a long time before I bought it as there are quite a few mud dobbber nests in the engine bay lol. Other than that it appears that the PO took very good care of the vehicle. 156K miles and no rust. Should I move forward with changing the alternator or is there anything else I should look at first? I have read on other posts about the voltage regulator but I am not familiar with testing. Seems that maybe high voltage would be problem if it is regulator. Maybe a ground wire somewhere?. Thanks for any help.

Two other things - volt meter does show minimal increase in voltage when increasing RPMs. She mentioned that the battery light turned on and off when hitting
bumps. This would lead me to think loose wiring but I cannot find any.

I agree with @suprarx7nut. R&R alternator. Best is a Toyota reman.

12.5 volts, is sign of a bad alternator! Provide you've good cable clamps to post connection. Which is simple to check; You should read same voltage directly on battery post as on cables down stream. I like testing/reading at a few points, to make sure grounds good also.

 

[Bomar]

Similar issues. I am 90 percent sure I need an alternator but since I am new to 100 series figured I would double-check on MUD before changing. Here is story -

Picked up a 2001 LX470 about a month ago. Already put about 4K miles on it with zero issues. I go out of town and my wife drives it (while her 4runner was in the body shop). Of course the day I leave she calls me and tells me the battery light is on. She was nearby the local Toyota dealer so I had her swing in for a quick check. Battery light went off before she made it in. They cleaned the terminals and checked for any codes. All checked fine. About 30 min later all dash lights started to come on. She turned engine off and it would not restart. Got my brother to come jump start. She made it home but he had to jump it a few times to make it. Fortunately my 80 series was running fine so she drove it until I got home a week later. Charged battery for about 30 min with jumper cables from my truck. Started up but battery light still on. Charged battery over night. Checked the battery (two years old) and it seemed fine. Brought a new battery home from work just to confirm. Same issue. Only reading about 12.5V when running with either battery. The wires seem to be OK. Fuses at + terminal check out fine. Belt seems fine (actually looks new). My cheapo code reader does not show any codes. This rig apparently set for a long time before I bought it as there are quite a few mud dobbber nests in the engine bay lol. Other than that it appears that the PO took very good care of the vehicle. 156K miles and no rust. Should I move forward with changing the alternator or is there anything else I should look at first? I have read on other posts about the voltage regulator but I am not familiar with testing. Seems that maybe high voltage would be problem if it is regulator. Maybe a ground wire somewhere?. Thanks for any help.

Two other things - volt meter does show minimal increase in voltage when increasing RPMs. She mentioned that the battery light turned on and off when hitting
bumps. This would lead me to think loose wiring but I cannot find any.

@tmoore41

I am fighting the exact same issue. I have replaced both batteries but per scan guage I never go below 13.9V.

Per multi meter my ALT is putting out 14.2V to batteries.

I am stumped b/c I have an Mechman 170amp alt to keep everything up to charge and I like it and it is 2 years old.

I haven't had any no start or battery dead issues. Just the light at speeds now or bumps. I have checked every connection I know to check.

 

[tmoore41]

Thanks for the responses. Gonna double check all grounds tonight. And also do the best I can to get a good look at the alternator. Have read about changing alternator from the top or from below. Have not secured an FSM yet. FSM combined with MUD has been my saving grace on the 80 series....Do you guys have a preference on changing alternator from top or from bottom? I love LC's but my 04 silverado is a much simpler alternator change lol.

 

[tmoore41]

Dumb question. Checked around for an alternator today. I can get a reman from Toyota for $235 but have to wait a day or two. Or pick up a Ultima 100amp reman from O'Reilly for $143 that says it is a rebuilt Nippodenso. Are these the same alternator?

Also read this thread on replacing: 100 series / lx470 alternator replacement quick tips no pictures - https://forum.ih8mud.com/threads/100-series-lx470-alternator-replacement-quick-tips-no-pictures.959695/ Alternator Replacement Steps. I'm still not clear whether it makes more sense to go from the top of engine or from below....

 

[suprarx7nut]

Reman from Toyota is different, in my experience. Not necessarily better, but not identical.

I did mine from beneath for most the job.

 

[tmoore41]

Gracias. Thanks all. Post when I get min to repair. Work and kiddos got in the way tonight.

 

[tmoore41]

Got the new one on. Ended going with the rebuilt from Toyota as suggested. The problem appears to be solved. FYI Toyota will not accept a "Non-Toyota" alternator as a core even if it is a Denso. Guess I have a core to get rebuilt for the future. Also, I originally went to get the Ultima rebuilt from O'Reilly. The salesman pulled it out of the box and pully was partially seized up. We determined It was bad and I decided to go with Toyota as suggested. Thanks for all the help. Going to add these comments and a little more follow-up to the post: Alternator Replacement Steps.