Battery Light On
- Thread starter nc-grayson
- Start date
brillo_76
Elite Member
I cant say i ever measured the voltage with an alt pigtail unplugged.. Maybe its normal as it might leak across the bulb from the other side. I am not sure on that one. That's an unknown. As that light is supposed to us know when there is a charging issue.
Is it a 1996? As I am telling you what the wiring diagram shows on the that wire. That wire I am speaking of goes from the light to the alt connector. The only splice in it is a feed from for daytime running relay that 1996 did not have in the United States at that time. Only The Canadian rigs I believe had daytime running lights.
The ignition circuit is separate from the charging one. Is your ignition switch shot? Are the contacts warn enough that the circuits are not fully connected.
As the battery idiot light if 1996 is showing its by itself.
So if your battery light is on and its feed wire plugs directly into the alt plug on the green/yellow has 4 volts coming out of the alternator the voltage regulator has an issue. If your just measuring it unplugged. Pull the 7.5 ignition fuse for a min. If it goes to 0 volts.. You know for sure that its nothing more then just bulb bleed through as current in normal bulbs can flow either way. Its only LEDs that block the flow of current the other direction.
The 2 white wires goto the alt (100amp fuse) and alt-s (7.5amp fuse) With the RL wire going to a junction and the gauge fuse..
The other side of the battery light is B-W goes to the ignition fuse.
The voltage regulator I would imagine could possibly still charge as those two white wires are coming directly off the generator feed.
Its telling you the regulator is having an problem. Whats the voltage at the battery with nothing on?
Whats the voltage a the battery at idle?
Whats the voltage at the battery when at 2K?
Its the voltage regulators job to keep the voltage really close to 13.8 to 14V.
As under normal driving conditions,. I haven't seen any stock 3rd gen go much above 14 volts. I few tenths ok.. But I never seen it 14.5v or above...Maybe others have. I just know I haven't as i have a voltage meter at the cigarette lighter and been watching voltages for about 10 years now on my 3rd gens as it maybe a tenth or 2 off of accuracy
13.8 to 14v is mostly the max.. If your over 14.5 volts, I say your voltage Regulator which is an integrated circuit maybe starting to go bad. They will fail to age. As well as get servery damaged when people throw those battery charges on Start and shove really high amps to the battery to get a rig started.
When that is done several times, you can kiss that voltage regulator good bye.
As that will burn them open.
Best to always jump with cables or capacitor jump boxes as they keep the voltage in line where it needs to be. Not to damage the regulator.
96 ToyRunner
Member
Mine was manufactured on 02/96, the ignition switch (not the tumbler so there’s no confusion lol )was changed 2 years ago but it checks out I pulled the 7.5 and there’s no continuity in the wire and there’s also no voltage to the yellow/green wire the voltage with nothing on the battery is 12.61 at idle it’s 14.25 (just cranked it ) battery reads 14.26 after turning on ac and headlight it reads alter is 14.30 and battery is 14.10…the battery light is still wide open
And I just bought this denso reman and have tested my self and at 2 other shops
I installed my old one and the battery light isn’t displaying on the dash on the on position at all
And I just bought this denso reman and have tested my self and at 2 other shops
I installed my old one and the battery light isn’t displaying on the dash on the on position at all
brillo_76
Elite Member
Now that is very interesting.... No wonder you scratching your head.
Those readings are perfect as its all below 14.5 even with decent load.
With your old one in... What does this green yellow wire read? Maybe the voltage regulator in the remain has issues. Would explain why its on and then the replacement is in. While it isn't on with the old one. Quality Control can be gong down hill and that's a possibility as to why its on with the new one. With nothing on that green wire.. Your bat light would be on. 0 volts would pull the plus 12 from the 7.5 Alt s side and 0 on the other side would light the bulb up..
If is below 12.4 or 12.0 the Bat light will light as well because it knows according to the voltage on the wire.. The system is not charging.
96 ToyRunner
Member
The old one the battery light isn’t on at including when the key is in the on position .Put a new negative terminal on and didn’t fix it ..I’ve had tbis truck for almost 15 years as a daily / weekend warrior and honestly done with it so if there’s anyone in or around north east Alabama it’ll be up for sale as a whole or parts hate to sound like a Debbie downer but crap don’t make sense and it’s been a headache of mine the past couple years
brillo_76
Elite Member
I hate to see you give up on it. Especially if its just an Alternator / wiring problem. However, I do understand the frustration at times..
This really just sounds like the alternator voltage regulator is defective and the remain Quality Control didnt check the alternator before they shipped it. :-(
As for the old Alt.. I would just need rebuilt with the a new voltage regulator as well.
In the past, by any chance did you super surge that battery circuit with battery charger and extremely high amps?? As that will cook the voltage regulators. As the its job is too keep the system voltage in a range and will burn itself up to accomplish this.
What can get them is these battery chargers in that start position 200 amp to the battery so the vehicle will start from a week battery. That will take out voltage regulators all day long. Always best to use jumper cables or those capacitor jump boxes to keep the amperage in check on the system.
You probably didn't. I just wanted to mention this for future readers that voltage regulators can only take so much and those start settings on a charger will let the smoke out of them... Its even worth mentioning a few times... They may survive a one or twice only if your lucky..
I see what my battery light is doing on my 1997. I really don't pay much attention to it as long as it is not on..
96 ToyRunner
Member
Alright update turns out I was one pin off so from the alternator to the gauge I have continuity from the ignition switch to the interior fuse box I have continuity now I’m trying to find the wire at the back of the fuse box to the gauge because from the gauge to the ignition switch I have no continuity …If I’m ready the diagram correctly the alternator L wire (y-g) goes to the light through the blue connector and checking the 1B pin (I have continuity ) comes out the white connector pin 9C goes down to the internal fuse 7.5 as a Gr-b ( I assume a grey with black stripe) comes out of the 7.5 as a B-R wire (Black with red stripe) and goes to pin ig2 in the ignition switch …I’m hoping I’m getting somewhere
96 ToyRunner
Member
Can’t find any continuity from the pin 9 on the white connector to the kick panel fuse box but the problem is I can’t find a diagram for that box so if anyone has one I would great appreciate it
96 ToyRunner
Member
Alright update after testing literally everything the problem was in fact the alternator ,I took my old factory one to get it rebuilt and after installing it and a hundred miles later the battery light is still off .Got to be one of the strangest faulty alternators I’ve delt with ( worked in a part store for a while) .
