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I hate to tell you, but that thich piece of white wire you're holding IS a fusible link, believe it or not. When you replaced it with a black fusible link, you changed the amperage rating at which it will fail. I don't know if it's a higher or lower rating, but it's different. NOT the right thing to do. You should have gotten one from Toyota, Rock Auto, something like that. That way you know you got the right amperage rating. A new one would come with the plate already installed. All you have to do it replace the fuses onto it, the way they are on the old plate.
Now, as to the truck not charging. I wager that if you ohm the wire between the large bolt on the side of the alternator and the battery positive terminal, you will find it's open, or at a high resistance. THAT would be your trouble. You should get the FSM's diagram (schematic) of the charging system. It will show the wiring you need to check. Like this:
The alternator
The engine fuse block feeding the battery
The wire from terminal B on the alternator (red arrow), the large bolt on the side of the alt with a red rubber cover over it, goes to the engine compartment fuse block (red arrow again). Ohm that wire out. I wager it's gone bad. That's probably where your charging problem is. Alternatively, the 80A fuse may be failed. Ohm it out too. Also, the fusible link to the battery could be failed. That's the one you replaced with black fusible link. all those things can be checked easily with an multimeter. With the schematic, you can easily see the path the charging power from the alternator to the battery takes.
Ok. I was finally able to view the video.
That's good for trucks without a starter relay. However his already has one. He merely needed to rewire it properly as I describe, and as RM Garage shows in his video
2TOYGUY and/or RAD4RUNNER -
Thank you for your reply 2TOYGUY...
Yes, your reply makes sense.
I haven't been able to find the fusible link [white wire with plate] anywhere online.
I tried checking Rock Auto and other places. Can you give me a link of where to buy this fusible link?
as to the truck not charging. I sistance
And... with my digital meter sat at OHMS / 200...touching big bolt on alternator to positive post on battery
I got a reading of 0.3 - is that good or should it have a reading of 0.0?
[and that's with the ignition switch off...right?]
Last edited by slowboy; Jul 5, 2023 at 06:02 AM.
Reason: ADD INFO
I hate to tell you, but that thich piece of white wire you're holding IS a fusible link, believe it or not. When you replaced it with a black fusible link, you changed the amperage rating at which it will fail. I don't know if it's a higher or lower rating, but it's different. NOT the right thing to do. You should have gotten one from Toyota, Rock Auto, something like that. That way you know you got the right amperage rating. A new one would come with the plate already installed. All you have to do it replace the fuses onto it, the way they are on the old plate.
Now, as to the truck not charging. I wager that if you ohm the wire between the large bolt on the side of the alternator and the battery positive terminal, you will find it's open, or at a high resistance. THAT would be your trouble. You should get the FSM's diagram (schematic) of the charging system. It will show the wiring you need to check. Like this:
The alternator
The engine fuse block feeding the battery
The wire from terminal B on the alternator (red arrow), the large bolt on the side of the alt with a red rubber cover over it, goes to the engine compartment fuse block (red arrow again). Ohm that wire out. I wager it's gone bad. That's probably where your charging problem is. Alternatively, the 80A fuse may be failed. Ohm it out too. Also, the fusible link to the battery could be failed. That's the one you replaced with black fusible link. all those things can be checked easily with an multimeter. With the schematic, you can easily see the path the charging power from the alternator to the battery takes.
Does all my rambling help any?
Pat☺
Yes, helped a lot... thanks for reply!
After checking wire from 'B' terminal battery, with meter on OHM 200... I got a reading of 0.3... I decided to check the battery with ignition off and it showed 12.79 volts...I started the engine and the meter was showing 14.45 volts, [charging].
Did you ohm out the 80A fuse in the engine compartment fuse block? What about the fusible link going to the battery? How about the battery terminals themselves? Have you tried pulling them off and cleaning them thoroughly? They must be bright and shiney, inside and out. What about the two main ground cables off the battery? One goes down to the engine block, usually on the AC compressor mounting bracket. The other should go to the body sheet metal. Often, just in front of the battery, just behind the headlight bucket. That's the really important one. But as long as it is bolted directly to the sheet metal of the engine compartment, that's what really matters.
I can't recall, but have you taken the battery in and gotten it load tested? That's the way to tell if it's any good or not. Is the fluid at the proper level? If not, add distilled water till it's at bottom of the fill tubes.
By the way, 200 times 0.3 is 60 ohms. That's awfully high for a wire. 0.3 on the 2 ohm scale is closer to reasonable. You might have wires corroded inside the insulation near the battery. It may well be enough to prevent charging properly.
Did you ohm out the 80A fuse in the engine compartment fuse block? What about the fusible link going to the battery? How about the battery terminals themselves? Have you tried pulling them off and cleaning them thoroughly? They must be bright and shiney, inside and out. What about the two main ground cables off the battery? One goes down to the engine block, usually on the AC compressor mounting bracket. The other should go to the body sheet metal. Often, just in front of the battery, just behind the headlight bucket. That's the really important one. But as long as it is bolted directly to the sheet metal of the engine compartment, that's what really matters.
I can't recall, but have you taken the battery in and gotten it load tested? That's the way to tell if it's any good or not. Is the fluid at the proper level? If not, add distilled water till it's at bottom of the fill tubes.
By the way, 200 times 0.3 is 60 ohms. That's awfully high for a wire. 0.3 on the 2 ohm scale is closer to reasonable. You might have wires corroded inside the insulation near the battery. It may well be enough to prevent charging properly.
Don't worry, we'll figure this out
Pat☺
sorry for delay in replying,
I haven't checked the ohm to anything so far but from the big nut on starter to the positive battery post, I've been busy and had to put yota on the back burner temporarily.
Not sure how to ohm the 80 amp fuse...or the black fusible link. Do I go from positive battery terminal to the 80 amp fuse?...and same for fusible link?
The battery is only 3 months old and connections to it are clean.
I did clean the ground to the fender well. Have not cleaned the ground from negative cable to a/c compressor, but I will.
Should I re-ohm from the alternator to positive battery post on the 2ohm scale and see what reading I get?
It's odd because sometimes alternator's charging the battery and sometimes not. When it 'is' charging it's reading 14.45volts.
I drove truck a couple miles and it did ok, but I was afraid to turn it off incase it wouldn't start back up when leaving the store.
Anyway thanks for your help and I'll check what you mentioned.
The best way to ohm out the fusible link and/or the 80 A fuse are out of the system. That way you're certain you're not getting a reading though the circuit it's in. If you know how to get to the two bolts on the 80A fuse, you know how to remove it. Same with the black fusible link. Take it completely out of the circuit, ant put the ohm meter on it, on the 2 ohm scale. It should read as close to 0 ohms as it can be. Anything higher than 1 ohm is a bad reading.
Same with the fusible link between the battery and the alternator. Pull both ends off, and put the meter on to measure it. Preferably on the 2 ohms scale. A wire should read very nearly 0 ohms. Like I said last time, 0.3 on the 200 ohm scale is 60 ohms. Way too high. I wager that if you measure it on the 2 ohm scale, it'll show OL, or higher than the scale can read. It may even on the 20 Ohm scale, depending on your meter. If so, you'll need to replace it, end to end. That doesn't mean just run a 12 GA wire through the loom, and connect both ends. It means try your very hardest to find a OEM replacement.
Whatever, your alternator will show charging if the voltage the battery sends to it is below a specific point. If it drops below that specific point, the alternator will switch to charge mode, and once the battery's voltage is above the specified point, the alternator will no longer charge the battery, nor will it need to. I don't recall off the top of my pointy skull what wire is the sensor wire to the alternator, to cause it to charge the battery, nor do I recall the required voltage reading to stop the charging.
Remember, the truck runs off the battery, and the alternator keeps the battery charged up while the truck is running. That way, should the alternator fail, the truck will a) let you know with the emergency brake and charge lights on at the same time, and b) The truck will continue to run, long enough to say, get you off the freeway, or maybe get to a mechanic, or even get home. It all depends on the drain you're putting on the battery at any given time. The lights on or off, and so forth. The less drain on the battery, the further it will take you before it gets to the point it can no longer run the engine, transmission (if an AT), and so on.
Remember, remove the negative battery terminal(s) BEFORE ohming ANYthing out. It only takes a very low current through the meter to blow it on the Ohms readings. Most meters have a fuse on the ohm readings to prevent damage to the entire meter.
The best way to ohm out the fusible link and/or the 80 A fuse are out of the system. That way you're certain you're not getting a reading though the circuit it's in. If you know how to get to the two bolts on the 80A fuse, you know how to remove it. Same with the black fusible link. Take it completely out of the circuit, ant put the ohm meter on it, on the 2 ohm scale. It should read as close to 0 ohms as it can be. Anything higher than 1 ohm is a bad reading.
Same with the fusible link between the battery and the alternator. Pull both ends off, and put the meter on to measure it. Preferably on the 2 ohms scale. A wire should read very nearly 0 ohms. Like I said last time, 0.3 on the 200 ohm scale is 60 ohms. Way too high. I wager that if you measure it on the 2 ohm scale, it'll show OL, or higher than the scale can read. It may even on the 20 Ohm scale, depending on your meter. If so, you'll need to replace it, end to end. That doesn't mean just run a 12 GA wire through the loom, and connect both ends. It means try your very hardest to find a OEM replacement.
Whatever, your alternator will show charging if the voltage the battery sends to it is below a specific point. If it drops below that specific point, the alternator will switch to charge mode, and once the battery's voltage is above the specified point, the alternator will no longer charge the battery, nor will it need to. I don't recall off the top of my pointy skull what wire is the sensor wire to the alternator, to cause it to charge the battery, nor do I recall the required voltage reading to stop the charging.
Remember, the truck runs off the battery, and the alternator keeps the battery charged up while the truck is running. That way, should the alternator fail, the truck will a) let you know with the emergency brake and charge lights on at the same time, and b) The truck will continue to run, long enough to say, get you off the freeway, or maybe get to a mechanic, or even get home. It all depends on the drain you're putting on the battery at any given time. The lights on or off, and so forth. The less drain on the battery, the further it will take you before it gets to the point it can no longer run the engine, transmission (if an AT), and so on.
Remember, remove the negative battery terminal(s) BEFORE ohming ANYthing out. It only takes a very low current through the meter to blow it on the Ohms readings. Most meters have a fuse on the ohm readings to prevent damage to the entire meter.
Does that help explain things a little?
Pat☺
Thanks for reply...
I'll do as you say and let you know the outcome.
Thanks again,
Keith
I'm sorry I get so wordy sometimes, but I'd rather give you too much information than too little. If you want me to cut back on the explanations, I will. It's just an old, bad, habit I have.
I'm sorry I get so wordy sometimes, but I'd rather give you too much information than too little. If you want me to cut back on the explanations, I will. It's just an old, bad, habit I have.
Anywho, I wish you all the best!
Pat☺
Not a problem with your explanations. At least I know you are definitely trying to help.
And you are looking very knowledgeable. I really appreciate all you do!
One thing I'm wondering is when I took the ohm reading on the alternator, I didn't
disconnect the negative battery cable. Should I have done that before ohming the
alternator too?
And another thing I'm wondering about is...if the battery reads 12.76 volts before starting
truck, will the alternator not show charging until the battery drops to a certain voltage while
truck is operation? [I hope this question makes sense too].
As far as ohming goes: YES, you should pull the battery negative before taking ohm readings anywhere in the truck. It will prevent damaging the meter.. I pull the battery negative terminal before ohming anything at all. Just to be safe.
As to the battery after starting: Remember that starting the truck puts a very heavy draw on the battery. It will almost invariably make the alternator go into charge mode after a start. The starter is a large, heavy draw motor. Using it will lower the battery, even a max charged one, enough to need charging.
Did you ohm out the 80A fuse in the engine compartment fuse block? What about the fusible link going to the battery? How about the battery terminals themselves? Have you tried pulling them off and cleaning them thoroughly? They must be bright and shiney, inside and out. What about the two main ground cables off the battery? One goes down to the engine block, usually on the AC compressor mounting bracket. The other should go to the body sheet metal. Often, just in front of the battery, just behind the headlight bucket. That's the really important one. But as long as it is bolted directly to the sheet metal of the engine compartment, that's what really matters.
I can't recall, but have you taken the battery in and gotten it load tested? That's the way to tell if it's any good or not. Is the fluid at the proper level? If not, add distilled water till it's at bottom of the fill tubes.
By the way, 200 times 0.3 is 60 ohms. That's awfully high for a wire. 0.3 on the 2 ohm scale is closer to reasonable. You might have wires corroded inside the insulation near the battery. It may well be enough to prevent charging properly.
Don't worry, we'll figure this out
Pat☺
ok...
I removed the negative battery cable...with my meter, on the 2 ohm scale...I removed the 80 amp fuse from the power distribution center, and removed the
The best way to ohm out the fusible link and/or the 80 A fuse are out of the system. That way you're certain you're not getting a reading though the circuit it's in. If you know how to get to the two bolts on the 80A fuse, you know how to remove it. Same with the black fusible link. Take it completely out of the circuit, ant put the ohm meter on it, on the 2 ohm scale. It should read as close to 0 ohms as it can be. Anything higher than 1 ohm is a bad reading.
Same with the fusible link between the battery and the alternator. Pull both ends off, and put the meter on to measure it. Preferably on the 2 ohms scale. A wire should read very nearly 0 ohms. Like I said last time, 0.3 on the 200 ohm scale is 60 ohms. Way too high. I wager that if you measure it on the 2 ohm scale, it'll show OL, or higher than the scale can read. It may even on the 20 Ohm scale, depending on your meter. If so, you'll need to replace it, end to end. That doesn't mean just run a 12 GA wire through the loom, and connect both ends. It means try your very hardest to find a OEM replacement.
Whatever, your alternator will show charging if the voltage the battery sends to it is below a specific point. If it drops below that specific point, the alternator will switch to charge mode, and once the battery's voltage is above the specified point, the alternator will no longer charge the battery, nor will it need to. I don't recall off the top of my pointy skull what wire is the sensor wire to the alternator, to cause it to charge the battery, nor do I recall the required voltage reading to stop the charging.
Remember, the truck runs off the battery, and the alternator keeps the battery charged up while the truck is running. That way, should the alternator fail, the truck will a) let you know with the emergency brake and charge lights on at the same time, and b) The truck will continue to run, long enough to say, get you off the freeway, or maybe get to a mechanic, or even get home. It all depends on the drain you're putting on the battery at any given time. The lights on or off, and so forth. The less drain on the battery, the further it will take you before it gets to the point it can no longer run the engine, transmission (if an AT), and so on.
Remember, remove the negative battery terminal(s) BEFORE ohming ANYthing out. It only takes a very low current through the meter to blow it on the Ohms readings. Most meters have a fuse on the ohm readings to prevent damage to the entire meter.
Does that help explain things a little?
Pat☺
Ok, first I removed the negative battery cable...I then removed the 80 amp fuse, and the fusible link between the battery and power distribution center...both of these showed '0' using the 2 scale on my meter...as far as the fusible link between the battery and alternator, where/which wire is that?...
Now I don't have any kind of power, no headlights and nothing when I turn ignition switch to the 'on' position...
as far as the fusible link between the battery and alternator, where/which wire is that?...
That's the big, white wire that goes from the heavy bolt on the side of the alternator over to the engine room fuse block. I'm pretty sure it bolts onto the plate that holds the 80A fuse and all the rest.
Now I don't have any kind of power, no headlights and nothing when I turn ignition switch to the 'on' position...
I am going to presume you put everything back together? Correctly?
You might want to double check your work. Maybe take it all apart again, and carefully put it all back together one item at a time. The 80A fuse, the fusible link, etc. DON'T put the two battery terminals back on until you're certain everything is connected correctly.
If you still don't have power where you need it, start checking fuses. In the engine compartment block, and the fuse block in the cab, behind the driver's side kick panel. Pull each and every fuse out and ohm it out like you would a wire. That's what they really are, after all. Check your grounds, too. A ground wire that pulled out of it's ring terminal can open a number of circuits. They can be hard to find, but stick with it.
Let us know what's going on with all this fun stuff
Pat☺
That's the big, white wire that goes from the heavy bolt on the side of the alternator over to the engine room fuse block. I'm pretty sure it bolts onto the plate that holds the 80A fuse and all the rest.
I am going to presume you put everything back together? Correctly?
You might want to double check your work. Maybe take it all apart again, and carefully put it all back together one item at a time. The 80A fuse, the fusible link, etc. DON'T put the two battery terminals back on until you're certain everything is connected correctly.
If you still don't have power where you need it, start checking fuses. In the engine compartment block, and the fuse block in the cab, behind the driver's side kick panel. Pull each and every fuse out and ohm it out like you would a wire. That's what they really are, after all. Check your grounds, too. A ground wire that pulled out of it's ring terminal can open a number of circuits. They can be hard to find, but stick with it.
Let us know what's going on with all this fun stuff
Pat☺
Thank you for your reply!
I rechecked grounds and found one I had missed. There are 2 different grounds on the fender well.
One from battery negative cable, and the other, not exactly sure. I didn't look that close at it but looks like maybe
somewhere under the engine bay fuse box. This ground has 2 white wires together and connect to
fender well on the opposite side of the engine bay fuse box. I guess the 'white' wires threw me off.
The bolt that screws into fender well was rusted and apparently not making good contact with the threaded insert
on the fender well that it screws in to. I cleaned the contact area of the wire connector and sanded down the fender well
where the connector made contact and everything started working like it should. I probably should put some primer
there where I sanded now that the truck is back together and hopefully fixed... [fingers crossed].
Hopefully it's fixed now, my son drove it to work this morning...[fingers crossed and prayers sent above].
I did a lot of avoidable things trying to fix truck, but I guess all-in-all I know that the starter is good,
and that the alternator is good too.
Thank you Pat for your time and direction!
I'll be sure to let you know of any future problems, if any, concerning this fiasco.
Don't paint over the bare metal where the wires screw into the fender. Keep it nice, clean, shiney metal.
There's a ground for the head(s) behind the engine, in the firewall. Just about center top of the firewall. It is a wire from the lifting hook bolt, on the bottom of the hook, to back behind the engine in the firewall. It's what provides ground to the head(s). Very important, because that's where the spark plugs get their ground. No ground, no spark. No spark, no fire. It also provides the alternator's ground, if the wire from the alternator up to the power steer pump's mounting is good, and conected properly.
Amazing what problems grounds can create, it really is. Bear in mind, the heads may be bolted into the engine block, but the need a separate ground. They don't have a very good connection, electrically, to the block.
Glad you got it working properly, assuming it does. Enjoy driving your truck!
Pat☺
Jul 4, 2023 | 11:48 AM
