When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
As Max said that red circle will only have power when the key is turned to start. If you look on the black part you should see a little "S" and the other stud a "I"
The blue circle connector is the regulator, the gray box.
If you look at the white part of the regulator it has letters that should match what Dave posted for testing.
You can put your test prob in were the wire is or use a paper clip to fit in next to the wire and your meter to the clip.
There should not be a need to remove the plug at this time but if you were to push in on the clips at the top & bottom then pull the plug from the regulator.
Also with the picture I can see you do not have a fuse link on the wire from the solenoid to ALT and should be installed.
Dave ----
the truck was on and no volts to it the regulator was received power and let's assume im a child when it comes to this stuff could the fusable links help or possibly fix my issue, every day i learn something new here. I plan to get new battery cables here soon and are fusible links Universal?
the truck was on and no volts to it the regulator was received power and let's assume im a child when it comes to this stuff could the fusable links help or possibly fix my issue, every day i learn something new here. I plan to get new battery cables here soon and are fusible links Universal?
When you say truck was "on", we assume that means the engine was running ? To be clear, tell us the engine was running.
Some could take, "being on" as meaning the Key was in the "on" position. There are some test where the "key is placed in the ON" position.
With engine running, do you have 12+ V on the post on the + post on the back of the Alt ?
I also question that yellow wire from the battery Neg to the fender under the solenoid, That should not be needed, the battery Neg (ground cable should attach to the frame and then to engine block.
My 86 Neg cable goes to the frame and engine block on the front right corner of the engine near the front of the oil pan.
The auto parts store should have fuselinks, they are different amp rating for them. see the EVTM link in post 29 to garys site, to see the correct links.
You can see the fuse links on my positive post on my solenoid in the photo above, my truck has three links there.
Last edited by Max Capacity; Feb 21, 2026 at 02:25 PM.
the truck was on and no volts to it the regulator was received power and let's assume im a child when it comes to this stuff could the fusable links help or possibly fix my issue, every day i learn something new here. I plan to get new battery cables here soon and are fusible links Universal?
I dont understand what truck on / no power to regulator means?
DaveF made a post what each of the wires, with the letters I think, should do with the key off & on.
So you need to follow that and report back what you find.
Yes, the wire that has the nut on it. Looks like you physically followed it to the battery +. But is it electrically good? With the engine off, take your meter or testlight and probe the large wire under the nut on the alternator. With the other lead on the negative of the battery, see if you have 12v there. What did you get?
If you don't have 12v, there is a problem in that wire. If you do have 12v;
Go down to the regulator. You may have to unbolt it to see it better. The terminals on the regulator are I A S F. If you have a ammeter in the dash, the I terminal will be blank. Yours looks to be blank
The A terminal will have a yellow wire. Check this wire, with the engine off, there should be 12v on the A terminal. What did you get?
The S terminal will have a lightgreen/red wire on it. With the key off, this wire should have 0v on it. With the key in run, this wire should have 12v on it. This wire comes from the ignition switch and tells the alternator to charge. What did you get key off & on?
The F terminal will go directly to the alternator. If all the other terminals have the correct voltages, the F terminal should have some sort of voltage on it with the engine running. If it has nothing, and all the other terminal voltages were correct, the regulator is bad. What did you get?
You have to methodically work through this. Fiddling around with the wires you might find a problem, but most likely not. You need to use a meter or testlight.
Run that test and let us know so we can guide you more.
For now you dont need the fuse link to see if the charging system works or not.
Based on where I see as long as that black wire from the ALT with the nut goes to the battery side of the solenoid and is good sould be ok.
But to answer your question, the fuse link does come in different sizes (ratings like normal fuses) my truck, 81 F100 with a 300 motor, has a 14 ga. fuse link installed.
But lets get the charging system checked out and working before we just to the fuel link.
Dave ----
I dont understand what truck on / no power to regulator means?
DaveF made a post what each of the wires, with the letters I think, should do with the key off & on.
So you need to follow that and report back what you find.
Run that test and let us know so we can guide you more.
For now you dont need the fuse link to see if the charging system works or not.
Based on where I see as long as that black wire from the ALT with the nut goes to the battery side of the solenoid and is good sould be ok.
But to answer your question, the fuse link does come in different sizes (ratings like normal fuses) my truck, 81 F100 with a 300 motor, has a 14 ga. fuse link installed.
But lets get the charging system checked out and working before we just to the fuel link.
Dave ----
Sorry im not trying to be difficult, while truck was running(engine running) i put my tester to all the circles and the red ones were getting voltage the white circle was not. I will try to get my tester on the wires in the regulator.
The black thing mounted to the fender with all your red circles. Get off that and forget about it. That is the starter relay. It has to do with cranking the engine. So if the engine is cranking ok, no need to mess with that. Yes, get onto the regulator below. You do not have to have the engine running to do testing.
As the other Dave said, search out each wire. Find out what label it has, measure it, and write it down. I, A, S, F. Search each one and see what you have from the negative of the battery to that terminal. Test the S terminal with the key off, and then the key on, the engine does not have to be running.
Red circle is getting no volt and I don't really see a way to open blue up to check but I did put my tester to the base metal of it and it is getting 12.2 volts so is everything else only the red wire with the red circle has no current.
If you are measuring 12 volts on the metal part of the voltage regulator it means the voltage regulator is not being grounded to the metal inner fender.
Add a ground, or fix the voltage regulator mounting screws so it is getting a ground.
The charging system (alternator) won't work if the voltage regulator isn't properly grounded.
Good call Jim on the grounding of the regulator case to the fender.
I see he has a wire to ground the solenoid wonder if there is a truck grounding problem?
Also dont know how he was using the meter as I would never think of measuring volts from the regulator case to ground?
I think we will let him get back on what he finds when he checks the regulator plug wires for volts and then go from there.
You know it hurts when you see things like this and know in like 10 minutes you could have this checked and maybe find the problem(s) but it is what it is
What state / city are you in maybe some member is close by and can give you a hand?
Dave ----
Good call Jim on the grounding of the regulator case to the fender.
I see he has a wire to ground the solenoid wonder if there is a truck grounding problem?
Also dont know how he was using the meter as I would never think of measuring volts from the regulator case to ground?
I think we will let him get back on what he finds when he checks the regulator plug wires for volts and then go from there.
You know it hurts when you see things like this and know in like 10 minutes you could have this checked and maybe find the problem(s) but it is what it is
What state / city are you in maybe some member is close by and can give you a hand?
Dave ----
I live in Missouri but outside of the thing I said is getting now volt from everything I've been getting so far im leaning on the regulator being fried or has issues im try to test the wires but i cant it the plug out easy and im getting nothing when i put the tester elsewhere for it again im a novice for this and when the wind dies down with the sharp cold i get back out there
I live in Missouri but outside of the thing I said is getting now volt from everything I've been getting so far im leaning on the regulator being fried or has issues im try to test the wires but i cant it the plug out easy and im getting nothing when i put the tester elsewhere for it again im a novice for this and when the wind dies down with the sharp cold i get back out there
You may want to unbolt the regulator and try and unplug it then. If you break the connector, you should be able to a replacement pigtail from NAPA.
It's been said, you can slip a paper clip (small piece of wire) into the back of the connector too for testing.
If you unbolt the regulator without disconnecting the bat you will damage the regulator. It grounds thru the frame!
Ok, then he needs to remove the battery cable first.
Speaking about the battery cables... the ones he has are... okay, I'll stop now about how bad those are...
Looking at his voltage regulator, I think he needs to lift up that white tab and then squeeze the two blue tabs on the sides of the blue connector and pull it out... ?
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Slideshow: The VelociRaptor Expedition gains a lift, upgraded suspension, Brembo brakes, and trail-ready equipment while retaining the stock 440-horsepower EcoBoost V6.
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
