Could this be my Alternator or Voltage Regulator or......

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jynx

jynx

Turd Herder
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Ok so I have been chasing a gremlin that has plagued my head lights and dash lights.

Backstory: Several months ago my high beams "stopped" working when switched to high, the flash still worked but no regular highs. So my dash lights had started to fad when at a stop. Fast forward a few months and I notice that the low beams would brighten and dim at random and when they would brighten up that all of a sudden the high beams would work.

So tonight I notice that the voltage gauge in the dash would rise and fall with the surges.
This is how the gauge reads most of the time. When here the high beams don't work.
ForumRunner_20121214_223305.webp

I will try to get a picture of the "surge" voltage but for reference it is near the line just below the "18V" reading, not the fat one, the skinny one that is actually the second from the top. When it bumps up that high, the high beams work again momentarily until the voltage drops off.

So now my question is: could this be a problem with the alternator or voltage regulator there-on? I know that most Toyota stuff is switched on the negative side so could it be the result of a bad ground somewhere, and if so where is a good place to start looking.

I am planning to call Slee to get their headlight harness to see if that helps but now I am more worried about a surge knocking out something else in the system.

I would appreciate any input

Thanks,

Matt
ForumRunner_20121214_223305.webp
 
Can you take it by an auto part store and have them hook up your truck to their charging system monitor/tester? Maybe that would send you in the right direction. Autozoo and o'reily's does it around here.
 
x2 on getting it tested.

Might be the regulator... in which case that's not a cheap part - $120 IIRC.

Edit: Toyota regulator is $140-$180, depending on who sells it to you.
 
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Yeah I can take it down later today or tomorrow, but will the test show what is going on unless it surges while being tested?
 
There are different tests - the best one (IMO) is the bench test, but that requires you to remove the alternator from the vehicle.

There are other tests that will do various charging/discharging/load diagnostics... but if your voltage is spiking that high, that's the sole job of the voltage regulator to keep that in check, which is why I'd suspect that above anything else.

And yes, you're quite right in worrying about other electronics getting damaged - get this fixed before something else gets hurt ;)
 
Have you checked (cleaned) ground connections at the battery (one to the block, one to the body?

For high beams to "come & go" sound a lot more like a bad ground or bad connection than an alternator/regulator 'surging'...

Check all your fusible links while you're at it (make sure all the bolts for those are tight). Check the +ve feed from the alternator to the battery and make sure it is clean & tight.

Put a meter across the battery (once you've cleaned battery grounds & +ve feeds). Check voltage with engine idling, rev up the engine to 1500 - 2000rpm and check voltage again. Report back.

A multimeter across the battery will provide a lot more useful info than the dumb meter in the dash.

cheers,
george.
 
Ok, so at idle I am getting 12.7 - 13.3 volts, when rev'd to 1500 rpm I am around 13.9 - 14.0 volts. Duplicating the "spike" is not easy since it just kind of happens, but while I was fooling around with it I got a brief flash and saw a spike up over 16 volts. Around 16.2 I think and then it dropped back off. Engine off I am seeing around 12.6 volts still.

Sooo based on those readings it would appear that the alternator is on its way out. And since the VR is integral to the Alt, (correct?) then it could be going or could have already gone bad and is why I am getting the random spikes.

Below is where the gauge jumps to during a "spike"

ForumRunner_20121216_164254.webp

The spike is also rpm related if the gauge is at least relative. During a spike at 2000 rpm it was very high on the gauge and would drop off if I let the rpm's drop.

I still need to check the connections but based on the alt readings would that not suggest that is where my problem lies?

Not sure this is tied to the high beams, because if they only work when I see over 15 - 16 volts then I am guessing I still have a ground issue somewhere and at a high voltage it just basically pulls itself "closed". Maybe? Thoughts.

Thanks guys.
ForumRunner_20121216_164254.webp
 
jynx said:
Ok, so at idle I am getting 12.7 - 13.3 volts, when rev'd to 1500 rpm I am around 13.9 - 14.0 volts. Duplicating the "spike" is not easy since it just kind of happens, but while I was fooling around with it I got a brief flash and saw a spike up over 16 volts. Around 16.2 I think and then it dropped back off. Engine off I am seeing around 12.6 volts still.

...
Click to expand...

What are you doing when you are "fooling around" - with the wiring etc... ???

Personally, I would FIRST check and fix ALL grounds between the battery and body/chassis. Clean the battery lugs (remove the battery clamps). Ensure all fusible links are intact and making a solid connection. Verify that the alternator plug and wiring is solid and reliable.

If that doesn't solve the issue, then I'd look at the alternator/regulator.

cheers,
george.
 
jynx said:
Ok, so at idle I am getting 12.7 - 13.3 volts, when rev'd to 1500 rpm I am around 13.9 - 14.0 volts. Duplicating the "spike" is not easy since it just kind of happens, but while I was fooling around with it I got a brief flash and saw a spike up over 16 volts. Around 16.2 I think and then it dropped back off. Engine off I am seeing around 12.6 volts still.
Click to expand...

I'm not very electrically inclined, but out of curiosity, what is the "healthy" voltage range during normal driving conditions? Shouldn't the battery maintain a steady voltage, regardless of engine rpms? Assuming a single OEM battery set up and no additional electrical drain. The first pic on this thread shows the voltage gauge at about were mine is all the time. If everything is running correctly, then would you ever see a "spike"? Even when turning on the high beams? Thanks for any information on this. Sorry for the slight hijacking...
 
Well, fooling around in this case only implies hooking up the volt meter and using the throttle body to rev the motor.

I will start chasing grounds tonight and see how that goes.

Thanks
 
grain2glass said:
I'm not very electrically inclined, but out of curiosity, what is the "healthy" voltage range during normal driving conditions? Shouldn't the battery maintain a steady voltage, regardless of engine rpms? Assuming a single OEM battery set up and no additional electrical drain. The first pic on this thread shows the voltage gauge at about were mine is all the time. If everything is running correctly, then would you ever see a "spike"? Even when turning on the high beams? Thanks for any information on this. Sorry for the slight hijacking...
Click to expand...

You should see around 14.4V while driving along and battery charged. The alternator's regulator should maintain a reasonably constant voltage of 14.4V across the battery but this can vary a little depending on temperature.

With everything working correctly, there should not be any major variation except under heavy loads (winching, starting, massive light bar etc). The dash gauge is 'ok' as a gross problem detector, but I would still rather have a meter wired across the battery as a more accurate measurement tool when fault finding.

The alternator feeds power and senses voltage (for the regulator) after the fusible links. So, if there is any intermittent connection issues going on with the fusible links etc, then the regulator may increase voltage to the battery and create the 'spikes' that the OP is seeing. All that wiring and fusible links and connections need to be checked and cleaned/replaced as needed to ensure solid electrical paths are in place before proceeding further with fault finding.

cheers,
george.
 
Just as another point of reference, my Sequoia 150A alternator (modded into my rig) puts out 14.1V when charging - all the time, no matter the RPM. When the battery is topped off, this drops to 13.8 and stays there.

The only time it goes below that (from my meter, which is always plugged in and comes directly off of a separately run fused connection) is when I've got the winch going.
 
Well, I checked the grounds I could find: one on each fender and the main that goes to the AC compressor on the block, and all three are tight and look to be in good shape. The visible wires were solid with no visible damage. The fusible links are in place and aside from looking like they are 21 years old, look to be in good shape.

I checked voltage on the battery after sitting for an hour or so and it was 12.7V. I cranked it up and initially it was around 14.1V but after it ran for a few seconds it jumped to 17.55V and stayed there for a minute or so and then dropped back to 14.2V and stayed there until I shut it off. The jump was not provoked, I just started it up and went around to check the meter.

I also pulled the HL relay to check it and I think I managed to pop the coil inside because now I have NO headlights, tail-lights or running lights. Brake lights still work so day driving is good, just no night driving.

I think I have several issues all combining. Unless someone can tell me something else to check then I think I am going to see about pulling the alt and taking it to one of the parts stores to have it bench tested and then, pending the result go from there on the Alternator. I will go ahead and order a new fusible link to install and a new head light relay and will replace all associated fuses in the HL circuit and disconnect, clean and reconnect the connections I can find.

I think that the High beam problem is due to a bad combination switch (CS) and when the 17+ volts hits the switch it is enough to pull it closed. I think I am going to see about getting a Slee HL harness to see if that helps and if not I will see about swapping reworking the CS using a spare I robbed a wiper switch off of a year ago.

That is about where I am, but the CS problem has me puzzled because the high/ low switch seems so simple. It is just a spring loaded detent ball that locates the lever. Unless there is something else in there that I am missing I can't figure out why it won't work. If I can find another one then I may try and take it all the way apart to see if it can be cleaned and re-assembled.

Thanks for the help and I welcome any other thoughts on this.
 
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I had the same problem on my '93 80. Started as very internittant issue, with the dash lighting up like a Christmas Tree, all idiot lights would kick on, then go off and act normally. Occurred maybe once every 3 to 6 months to start with. It wasn't until later that it was happening more often and longer duration that I realized the voltage was spiking. Then it progressed to a daily thing, every time it would try to kick into high current charge. I didn't have the bucks for another alrternator, and drove it this way for way too long.
It will overcharge the battery, cause some components to fail during operation (aftermarket radio), and make you worry about the computer, relays, lights,etc., mine even broke one of the alternator belts and it started sqealing like a stuck FJ55 (PIG). Also embarassing to have the voltage kick high while driving at night, people think you are flashing your high beams.
Alternator is now replaced, along with rebuilt radiator, belts, and upper and lower radiator hoses. Only long term damage is maybe some life taken off my battery and my high beam relay, I click it on and only get the dash indicator but no high beams, I will be looking at that next. The voltage regulator and diodes are integral with the alternator. Nice to have reliability again. I think you should replace the alternator.
End the pain.
My .02.
:cheers:
Eric C.
 
fj45lv said:
I had the same problem on my '93 80. Started as very internittant issue, with the dash lighting up like a Christmas Tree, all idiot lights would kick on, then go off and act normally. Occurred maybe once every 3 to 6 months to start with. It wasn't until later that it was happening more often and longer duration that I realized the voltage was spiking. Then it progressed to a daily thing, every time it would try to kick into high current charge. I didn't have the bucks for another alrternator, and drove it this way for way too long.
It will overcharge the battery, cause some components to fail during operation (aftermarket radio), and make you worry about the computer, relays, lights,etc., mine even broke one of the alternator belts and it started sqealing like a stuck FJ55 (PIG). Also embarassing to have the voltage kick high while driving at night, people think you are flashing your high beams.
Alternator is now replaced, along with rebuilt radiator, belts, and upper and lower radiator hoses. Only long term damage is maybe some life taken off my battery and my high beam relay, I click it on and only get the dash indicator but no high beams, I will be looking at that next. The voltage regulator and diodes are integral with the alternator. Nice to have reliability again. I think you should replace the alternator.
End the pain.
My .02.
:cheers:
Eric C.
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So I have a 92 and I’m on the same boat as the person who made this thread and your post. I’m glad I found this, I read so much about how some go with a high amp alt vs OEM. I’m curious to know how yalls alt are working now a days . @jynx
 
andyvig said:
So I have a 92 and I’m on the same boat as the person who made this thread and your post. I’m glad I found this, I read so much about how some go with a high amp alt vs OEM. I’m curious to know how yalls alt are working now a days . @jynx
Click to expand...
Depending on the date of manufacture, your 3FE will have an 80 amp (external fan) or a 90 amp (internal fan) alternator. I don't believe there is a "high amp" bolt in unit available like there is for the 1FZ.
At one point Mean Green made them, but they had a horrible reputation.
Personally, I would stick with an OEM Denso unit, a high quality battery, and good cables.
 
I guess I should have updated this thread years ago. I bought a new OE unit. Don't recall if it was from the dealer or DENSO direct. It was slightly different than the one that came out. Both of them are/were internal fans. I had to do some grinding on the housing to clear the motor mount, but after that, it bolted it. It's been operating just fine for the last 12 years. So the answer to my original issue was that the internal regulator was bad and replacing the alt fixed the issue.

IMG_20130415_184419_977.webp
IMG_20130415_184430_921.webp
 
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