Need help with a charging issue

[BrantDale]

I have not been able to get my battery to charge. This is what i have done so far:

Checked the battery and it is reading 12.4-12.8 when not running, it is a new battery and worked fine.

When running reads same and starts to go down with accessories on, eventually running the battery down.

Took the alternator to auto parts store and it checked out good, changed the belt, it does appear a bit looser than I would like but it doesnt seem to be slipping.

I did a full-field test and bypassed the regulator and then got strong readings of 15-17, so I was sure it was the regulator, got a new one put it in and it is still not charging.

I cleaned the regulator ground connections, tried again and not charging. Ran a ground wire from regulator to the block to make sure it was grounded, still nothing.

I am at a loss to what could be going on, I am just learning about this stuff and using this site to help, so any ideas will be appreciated.

[seattle67]

Well, you've done a good job narrowing it down, you know your battery is good and you know your alternator works.

Two things come to mind, one is the off chance that your brand new regulator is bad. I know that sounds far fetched but you would be surprised how often it happens. The other thing I would look at is the wiring, confirm that the wiring is correct. I will attach a couple pictures that may help, one is for charging circuits with an ammeter and the other is if you have idiot lights.

[BrantDale]

Thanks for the response Dan.

Ok, so I checked the wiring to the diagrams, and it looks like it is correct. I also, took another regulator and tried that and the same results.

I am starting to wonder if the connector that goes into the regulator could be bad. But when I bypass the regulator with wires placed directly into the connector, it works. Based on the diagrams above, if the neutral terminal, on the connector, was bad would that cause it not to charge? The A and F terminal must work since it charges when i wire directly to it.

I have the indicator light but I am also having issues with the lights in my instrument panel, so I don't even know if that works, I think that is a completely different issue though.

[seattle67]

Your correct, it could be that the connector is not making a good connection when you plug it into the regulator, I would take a flashlight and try and look into the connector to see what condition it's in. Or it could be that a wire has broken in the connector, if you have a test meter with an "ohm" setting you could check for continuity on each wire from the connector to the alternator. The answer to your question regarding the "neutral" wire is yes, it needs to be in the circuit for the charging system to work correctly.

Good luck on this, I wish you were near, I would come over and help. I can usually fix this kind of thing quickly, but I'm not so good at explaining it to others. Maybe Shayne will jump in and offer his 2 cents, he's much better at making sense of it all than I am.

[BrantDale]

Ok, so i checked the connector and it all seems fine. But I did check the regulator that I just bought and it was not working (no connection between the A and F connection), so I went to the auto parts store exchanged it, checked the new one for continuity and it was good, so I was thinking I just got a bad regulator. But when I hooked the new regulator up and it blew that one too. So, now, the question is, what would cause the regulators to blow?

Thanks again!

[70_F100]

Short circuit causing it to ground out, or open circuit causing an over-charge condition.

[BrantDale]

How do you find a short circuit or an over-charge condition? I have a multi-meter, can i use that to find a short circuit? I know these are probably very basic things but I am new to the whole electrical thing. I am assuming a short circuit is when a "live" wire is in contact with something it shouldnt be?

This is probably stuff that has been addressed a 100 times on here, so thanks for your patience.

[Thunderfoot]

I have the indicator light but I am also having issues with the lights in my instrument panel, so I don't even know if that works, I think that is a completely different issue though.

I bet your problems Are related... The alternator wont charge until the Regulator is turned on, this signal comes from the ignition switch but it also feed power to the Alt light in the dash, so if something is wrong with that wire (shorted to ground or broken) it wont tell the regulator to turn on and activate the alternator.

Check that you have power on the (I) terminal with the key on, this is the signal to turn it on.
Also, you shouldn't have continuity between the A and F terminals on the regulator until you have power on the I terminal, the new one probably reset once you plugged it in...

For a system with the idiot light this is what is going on with the Voltage Regulator:
The I terminal is what turns on the voltage regulator, it has to be switched because if it was on without the motor running it would drain the battery.
The A terminal is the (Sense) terminal, it is reading the battery voltage to determine how much the alternator needs to charge.
The F terminal is the controller of the alternator, it varies a voltage to the alternator which controls how hard it charges...
The S terminal has voltage on it once the alternator starts charging, this voltage keeps the alternator turned on until the engine is turned off.

Probably more info then you wanted but... Anyway, I bet you don't have any power on the I terminal, it will be wire #904 in this diagram here http://www.fordification.com/tech/wirin ... rging2.jpg it is a Green/red striped wire.

If your Alt light doesn't come on with the engine off and the key in Run then this would also point to that (I) wire not being hooked up or an issue with it somewhere... (or just the light burnt out)

[BrantDale]

Thunderfoot, I think that you are right on the I terminal. I pulled the ignition switch and there was some burned wire and a loose wire. So, I got another switch and plug but the new switch and plug (off of a 69 F100) but the new one has only six wires and the old one had seven. I will attach some pictures of the old and new.

Any thoughts would be greatly appreciated. I hooked up the switch and made a connection with the 7th "pink" looking wire, in the hole that didnt have a wire, and still no charging through the regulator. One other question, does the instrument panel need to be connected to make it work?

This is how it looked when I pulled the switch, the "pink" wire was just loose and the yellow was a bit fried


This is the front of the plug, it had some melted areas


This is the plug off of a 69 donor truck but it only has six wires and the hole on the upper right doesnt have a connection

[Thunderfoot]

Yikes! the melted connector wasn't good...
The Instrument panel doesn't have to be plugged in for the Alternator to work.
That empty hole on the plug is normal and not used, so no wires in it.
That wire looks more Violet then Pink in the photo which would/could be the wire for the Alternator, the other wire I see in the pic (Pink wire) that is with the Red/yellow striped wire looks pink to me . A Pink wire would be the wire for the coil, it is a resistive wire just as the Alternator wire would be...

The alternator wire should be either Violet (Light purple) or Black (depending on year of truck and options) on the switch connector and it should be in the same location with the Black/green striped wire.

What year is your truck?

[BrantDale]

I think I am a bit color blind, but I do see what your talking about. So the violet wire should be with the black/green wire? If so, I will try that and hopefully that will solve all my problems .

This truck is a 69 F100 Ranger.

Thanks for all of your help. This is a great site and a incredible resource and everyone seems to be very willing to help.

[BrantDale]

It is a 68 F100 Ranger my donor truck is a 69 F100 Custom. Just noticed I said it wrong in the last post.

[Thunderfoot]

Yes, I would try that, the diagrams show it as a Black wire for that year but I have seen some mistakes on them so this might be one of them. It changes to a Violet wire in the later year diagrams.

[BrantDale]

Ok, so the alternator is now charging. Thanks for the help on that issue, now on to the next problem.

[Thunderfoot]

cool, glad that got it fixed up.