Bad diode causing baby light on???

Rsbhunter

New member
Posted before about my 2006 Sport having a batt light on. Checked batt, showed 11.6, replaced. Light still on, checked alt, 12 9 running....replaced alt.Now batt at 12.8, running , alt is 14.2, drops to 13.9, 14.1.....light still on . Alt harness is mint, every fuse has been checked, all the 7.5 replaced....scanned, clear...one member here mentioned that it might be a bad diode? Is there a diode that can trip the light (no 12v output for light) and will still let the alt charge normal? I'll replace the Remy rebuilt alt if there's a chance that a bad diode could cause this.....figure that someone on the site does electrical trouble shooting...Thanks, rsbhunter
 
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Posted before about my 2006 Sport having a batt light on. Checked batt, showed 11.6, replaced. Light still on, checked alt, 12 9 running....replaced alt.Now batt at 12.8, running , alt is 14.2, drops to 13.9, 14.1.....light still on . Alt harness is mint, every fuse has been checked, all the 7.5 replaced....scanned, clear...one member here mentioned that it might be a bad diode? Is there a diode that can trip the light (no 12v output for light) and will still let the alt charge normal? I'll replace the Remy rebuilt alt if there's a chance that a bad diode could cause this.....figure that someone on the site does electrical trouble shooting...Thanks, rsbhunter

Here's a link to search results on YouTube for testing alternator diodes, and other tests using a multi-meter, one or more of the videos may help you track down what the issue is.

https://www.youtube.com/results?search_query=testing+alternator+diodes+with+multimeter+
 
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Here's a link to search results on YouTube for testing alternator diodes, and other tests using a multi-meter, one or more of the videos may help you track down what the issue is.

That is for the diode-trio in the alt, I think the OP is talking about one of the steering diodes in the Instrument Panel that control the idiot lights.

The FSM has info on testing all that.
 
That is for the diode-trio in the alt, I think the OP is talking about one of the steering diodes in the Instrument Panel that control the idiot lights.

The FSM has info on testing all that.

I posted that because he was asking another member if he could test the diode with the alternator still in the vehicle.

Here's a link to their conversation on his profile page, I also saw it discussed in another topic as well.

https://www.toyota-4runner.org/converse.php?u=139095&u2=44255

It appears he hasn't visited the forum since he posted this topic so we won't know which diode his question is referring too until he returns and replies.
 
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Batt light on

Actually, I was asking about the alt diodes....this is driving me crazy....new battery, new (rebuilt) alt.... No blown fuses, wiring never messed with....truck has not been beat, has been on road for 99% of its life....everything is stock except for batt, alt....How many wires are supposed to come out of the alternator plug? Thanks, I'm 67 years old, have worked on my own cars since 15, and I'm not looking to have to replace the alt again, but I'm looking at a rebuilt Denso unit (this one is a Remy)from Summit Racing. If anybody feels that would be a mistake, PLEASE let me know, Thanks...rsbhunter
 
Battery light STILL ON!

Ok,broke down and put in a rebuilt Denso unit from Denso, California!!!! Yeah, no. Light still on....I'm done, I'll pay a technician $$$$ from Toyota dealer to figure it out.....can't believe there's not a Toyota technician on this site who hasn't run into this problem..... Guess it will be a piece of electrical tape that fixes this problem..... rsbhunter
 

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