1990 Toyota Pickup 3.0
I'm Having an ongoing issue with my voltage dropping terribly while driving to the point of dying. I replaced the alternator with a new one and that didn't fix it. I just replaced the wire that runs from the fusible link to the battery and that didn't work. When I use my turn signals and power windows or even my headlights the battery gauge will drop. I've checked just about every ground I can see under the hood. Any other ideas would be greatly appreciated. Thanks!

 

How old is your battery? Do you know if the battery is good?

Are the battery terminals super clean and shiny (best electrical connections are made when clean, shiny metal touches clean, shiny metal)?

 

I'm going to replace the terminals tonight and see if that helps. My buddy gave me a red top optima and it have 12.5 volts so I would assume that it is a good battery.

 

An adequate battery, as long as it is charged, will hold up the voltage even with a dead alternator. So a voltage drop with headlights means the battery isn't charged, or isn't taking a charge.

This is easy to check. With engine off, measure the battery voltage at the terminals with your multimeter. Should be around 12.6v. Turn on the headlights. If the voltage drops below, oh, 12.3v then the battery isn't charged. Charge it, repeat. If it still drops, replace the battery (or take it to any parts store; they'll test it on their carbon-pile tester.)

If the battery holds up but you have a voltage drop at the voltmeter (or anywhere else) with headlights, use your multimeter to find the bad connection. Just keep measuring voltage to negative terminal as you move closer to the current draw. When you pass the bad connection, the voltage will start dropping.

 

Not necessarily. Even a completely crap battery can be charged up to 12.6; it just won't stay there for long. I've suggested some tests; even if you have to BUY https://www.harborfreight.com/7-func...ter-90899.html the multimeter it will cost less than even the terminals you're replacing on a whim.

 

I will definitely do a test on it tonight. Thanks

 

what part of Alaska Johnny? If you're anywhere near the Kenai area I'll help you out if I can.

 

+1 to getting a multi-meter, testing battery and making sure ALL connections are good. Repeat: ALL connections to alternator and battery, not just the cliched "check grounds".

Now, that's Yota brothers helping one another...^^^

 

I’m up here in Fairbanks or I’d take you up on that man

 

had my battery tested and it checked out. Replaced the terminals with new ones and that also didn’t help. What in the world could it possibly be ?

 

Got a meter? test for voltage at your battery with the engine on and off and post your results

 

So the battery before starting was 12.8v
Started the truck- it went to 12.3v
turned on my hazards it bounced from 12.3v to 12.20v all in between.
Turned the lights on with the hazards still going and it dropped to 12.15v
sorry for taking so long to respond

 

what that tells me is your battery was fully charged, but your alternator isn't doing anything to keep it charged. check the connections from the alternator to the battery for power loss/bad connections. test the voltage at the alternator and see if it matches the reading at the battery when running. if not, fix the bad connection if so, check the circuits that energize the alternator, (sorry I don't have a wiring diagram maybe someone else can chime in here).

 

YES^^^

This is for 22REliable, but wires leading to alt should be the same. "IG" is the "wire that energizes the alt"
https://www.yotatech.com/forums/f199...l#post52094780

 

anyone have any insight on the Am2 30 amp fuse and the AM1 40 amp fuse ?
Fuse panel next to the battery

 

Absolutely.

Do you have a question?

AKWheeler had it right; your alternator is not charging. That's not AM1 or AM2 (which would take out a lot of other stuff, too.) Have you done the tests suggested?

 

So I went ahead and put a new alternator into it again and now it’s working like it should. I don’t know if maybe I forgot to connect something when I replaced it last time but she’s back to working condition. Thanks everyone for the help.

 

Congrats, you are welcome!

 

Glad you got it working
But you need to remember the suggestions above, in case it happens again.