Alternator Charging Issue

ledzilla · Dec 3, 2024

Ok, so I took a look at the wiring installation for the alternator, and I think I'm on the right track. Now, the wiring for the alternator's connectors is a different color because it was a different brand of alternator and conversion pigtails installed, but the connections look the same. That 1.3V wire is supposed to be switched 12V connected to the "blue" wire in the attached diagram. So, where ever that factory green wire runs, yeah, there has to be some damage to it where it occasionally loses some part of the circuit, either through internal damage to the wire or a bad connection at the other end. So if I either repair that wire or for now just run a separate wire providing switched 12V, in theory that should fix the problem.

I have also seen a few things that say the voltage sensing wire shouldn't be connected to the alternator's B terminal, but instead at the point where everything connects for power (along with a 10A inline fuse). In my current setup I'm not sure that will really make a difference since everything sources from the 350A distribution block I mounted to the wheel well. Those connections all feel pretty secure still.

Tiha · Dec 4, 2024

I don't remember which terminal to connect it to but it should be 12v on that wire. It energizes the alternator.

You don't have to, but I used a key switched source. In case something went wrong inside the alternator it wouldn't run the battery dead.

grumpy old man · Dec 4, 2024

For whatever it is worth I am working on an 89 B2 for my granddaughter. I was waiting in line for gas and noticed the charge indicator had dropped way down. I did not shut it off and started checking things out as soon as I got home. I was showing 14.2 at the battery with the engine running so am sure that it was charging but the gauge was still way down. The engine loom has been completely out of the car because of a code 41 I could not find or fix and was completely unwrapped. Every wire in it was checked with an ohmmeter from end to end and checked fine. I did find a resister in the O2 wiring that no one I have talked to has ever heard of, and yes it is a factory part. Just because I happened to have a new one in a box (one with the permanent pigtail that needed to be wired in) and just for giggles I installed it. The gauge came up about halfway to normal. and I drove it for another month without incident. I do not know what state yours originated in but it seems that Ford was doing wierd things to get those to pass Cal smog, and has wiring that does not show in any wiring diagram.

I am now in the process of curing ALL the issues with the B2 by sitting it on top of a shortened 07 Explorer chassis. I will be using the explorer wiring, dash and all other rlated stuff because I need to make it smog legal in the Peoples Republic of California. Drastic yes, but it is the only way to get a decent powerplant in it.

L\Bronco · Dec 4, 2024

ledzilla said:
I am seriously considering pulling everything and installing a new harness. But that's for down the road a bit. I'm working on doing that already for my '79 Marquis. Between California emissions parts I can't find anywhere and rodent damage to the wiring I'm not left with many options.

I spent some time checking things over until my hands got too cold (can't even put one hand into gloves right now). There are only two wires connected to the alternator. One is the 2ga charging wire that I installed. The other is tapped into the green wire connected to the original voltage regulator plug. I attached a photo of it. I tested the voltage on that wire and it was something like 1.3V. Looking at my available wiring diagrams, I don't see any modules sourcing power or resistors, so it seems like it should be a full 12V there. I wanted to start up the engine and see if maybe there was a difference with it running, but the cold sapped the battery and that damned charger once again failed to maintain the battery. I'll check it out again after the battery has a better charge. But, I'm guessing that maybe there's damage to that green wire somewhere causing a voltage drop. I'm thinking I should try running a fresh wire with switched power to that spot.

pull on the green wire where that scotch lock connector is. (they are horrible for introducing green death into wire. I think a replacement harness is the answer when you are up to it.
Cheers

ledzilla · Dec 4, 2024

OK, so went back out today, and the tested voltage was something like 0.05-0.10. I wiggled that connector around a bit and the voltage fluctuated wildly. So, I cut out the connector and tested voltage on bare wire, it was about 8V. Reconnected that wire to the alternator using some WeatherPack connectors. Still not charging. I verified that voltage was still coming through the connector. I'm going to poke at a few more wires/connections, but if that doesn't pan out I'm going to grab help from someone with two fully working hands to assist in pulling the alternator to get it tested. Make sure it didn't get damaged with this mess.

ledzilla · Dec 6, 2024

More poking, and more information. So, that green wire, it kicks out between 8V to 12.8V, but it seems to have no ability to support a load. Even with enough voltage, it won't power a relay. Connect the relay direct to battery, it switches. Connect it to that green wire, nothing. So I connected the wire from the alternator directly to the battery while it was running and the voltmeter reported back a charging voltage. The plan now is to run a switched voltage from the fuse panel to a relay under the hood, and have that relay connect 12V to the alternator. I should definitely run a fuse between the alternator and this relay connection, just not sure how big it will need to be. There might be a clue is the wiring diagrams as to what would be appropriate.

L\Bronco · Dec 6, 2024

ledzilla said:
More poking, and more information. So, that green wire, it kicks out between 8V to 12.8V, but it seems to have no ability to support a load. Even with enough voltage, it won't power a relay. Connect the relay direct to battery, it switches. Connect it to that green wire, nothing. So I connected the wire from the alternator directly to the battery while it was running and the voltmeter reported back a charging voltage. The plan now is to run a switched voltage from the fuse panel to a relay under the hood, and have that relay connect 12V to the alternator. I should definitely run a fuse between the alternator and this relay connection, just not sure how big it will need to be. There might be a clue is the wiring diagrams as to what would be appropriate.

Hey Led, I was looking at your picts, that one in post 20, is that the old remote regulator plug?
If so, the green wire should come from the charge bulb.
(12v to bulb to green to regulator to excite the circuit. If you ground it the charge light should come on.
So there should be 12v there with the key on and the alt unplugged.
Hope that helps
Cheers

ledzilla · Dec 6, 2024

L\Bronco said:
Hey Led, I was looking at your picts, that one in post 20, is that the old remote regulator plug?
If so, the green wire should come from the charge bulb.
(12v to bulb to green to regulator to excite the circuit. If you ground it the charge light should come on.
So there should be 12v there with the key on and the alt unplugged.
Hope that helps
Cheers

Yes, that would be the original voltage regulator plug. But, interesting fact, my Bronco does not appear to have a warning light, it has a gauge. I took a look at the info from the manual which gives no information on what exactly the gauge should be telling the driver. But with my testing, that wire only was getting 12V when 12V was supplied to the alternator from elsewhere. So, I imagine that there is an issue with that wire somewhere to prevent 12V from being supplied. It apparently worked doing what it was supposed to do for quite a long time, but that no longer appears to be the case. I just find it odd that there was not even enough power flowing through that wire to trigger a relay.

L\Bronco · Dec 6, 2024

ledzilla said:
Yes, that would be the original voltage regulator plug. But, interesting fact, my Bronco does not appear to have a warning light, it has a gauge. I took a look at the info from the manual which gives no information on what exactly the gauge should be telling the driver. But with my testing, that wire only was getting 12V when 12V was supplied to the alternator from elsewhere. So, I imagine that there is an issue with that wire somewhere to prevent 12V from being supplied. It apparently worked doing what it was supposed to do for quite a long time, but that no longer appears to be the case. I just find it odd that there was not even enough power flowing through that wire to trigger a relay.

Ill do some digging on monday and see what I can come up with.
Cheers

ledzilla · Dec 9, 2024

I made my little harness and hooked it up. It's not pretty, but it works. Don't have time today, but tomorrow I'm planning to drive around a bit, see how the voltage handles. Definitely going to hit the gas station, since the tank is nearly empty.

L\Bronco said:
Ill do some digging on monday and see what I can come up with.
Cheers

I'm looking forward to what you're able to find. I don't want this harness to be a long-term fix.

L\Bronco · Dec 11, 2024

So, I found one with a charge gauge. The green wire comes from the ign switch “directly”, so, should be 12-14v for sure.
Sorry, I can’t remember the exact year of yours, let me know and Ill post the diagram so you have something to work from.
Cheers

ledzilla · Dec 13, 2024

Thanks for taking a look. Mine is an '83.

It's a little frustrating since there appear to be errors in the diagram I have on hand. It shows that to be a black wire with green stripe, so I'm curious what other errors exist, most notably the wire that's supposed to run from the ignition switch to the solenoid. I think it was also wrong about the other wire colors running to the voltage regulator connector.

L\Bronco · Dec 13, 2024

If I can find a good one, Ill post it here

goffprof · Dec 14, 2024

ledzilla said:
So, yes, looks like I have yet another alternator issue. I've had a few issues where I'd come out to my Bronco, but there wasn't enough juice in the battery for it to start. I ended up swapping batteries a couple times in the last month or so from the local junkyard (one battery wouldn't hold a charge at all). I was thinking that I had some sort of weird parasitic draw even though the only pull on the battery when not running was the radio's memory circuit (verified to be 0.3A draw when the battery connects and then reduces to below what my meter could read after several seconds, so less than 0.01A). So that wasn't the case. Then I noticed the last two times this occurred, I had driven some distance from home. I headed out in segmented runs, making stops and getting further. But it was just one straight shot home each time. No issues encountered while out and about, only after getting home and trying to start the Bronco again later on. The return journeys were all more than 30 minutes of driving with highway driving or travel on roads near highway speeds. On one of these drives, getting near home, I noticed the instrument cluster looked relatively dim and I tried fiddling with the dimmer switch, but it didn't help. Makes me think it was all running on reduced alternator output.

So, I'm of the mind that the alternator is the problem, but as with most things I don't think it has more than a one year length on the warranty. But assuming that it's not a quality issue with the alternator itself, could there be something else going on under the hood that could cause such an issue on longer drives like this? Maybe too much heat, something pulling an unexpectedly high draw on the alternator? Just want some things to look at before I try looking into replacing the alternator. I don't want to replace it only to have the same issue come back again.

I had a similar problem on my ‘96 EB Bronco where the battery would suddenly have low voltage, lights were dim, etc. I checked the 140A replacement alternator that was installed in ‘22 and it was working fine, charging at 13.5-14.8VDC depending on the battery voltage. Suspected a bad cell in my 2-year old EverStart Maxx battery. Brought it to WalMart, they tested it, found a bad cell, gave me a new one with a new 3-year warranty, no pro rating.

Alternator Charging Issue

ledzilla

Active member

Attachments

Tiha

Well-known member

grumpy old man

Active member

L\Bronco

Well-known member

ledzilla

Active member

ledzilla

Active member

L\Bronco

Well-known member

ledzilla

Active member

L\Bronco

Well-known member

ledzilla

Active member

Attachments

L\Bronco

Well-known member

ledzilla

Active member

L\Bronco

Well-known member

goffprof

New member

Similar threads

Members online

Latest posts

Forum statistics