charging system fiasco

[primordialpaul]

This truck is driving me out of my mind. Ive got a new alternator new battery, fusible links are good fuses are good, replaced terminals, im getting no charge and my battery light is on. Ive tested EVERYTHING. When i put the new battery in it was running at 14 or so volts, checked at alt yellow wire and battery. The green wire off alt is getting 2v or so im told this is correct. Im showing no voltage at white black wire. Ive got everything tight to the starter, ive got 12 v to side mounted solenoid on bottom post nothing anywhere else which i though was off but cant find correct info in a sea of charging system posts that have little or nothing to do with whats happening here. This blk wht stator wire, what voltage should it show while running and should the solenoid show votage elsewhere besides botton post? Any ideas welcome, im ready to junk this whole truck and never have to spin a wrench on it again.. nightmare.

 

[Dan Whitaker]

There is a fuse under the hood for the alternator. It's a 30 or 40 AMP. I went through this several years ago and it ended up being the alternator fuse was blown.

 

[primordialpaul]

There is a fuse under the hood for the alternator. It's a 30 or 40 AMP. I went through this several years ago and it ended up being the alternator fuse was blown.

Ive rechecked the fuses but it stands that none of them pertaining to the charging system are blown. Its not an issue with the fuses, they have 12v

 

[Turdle]

Check the connection down on the starter.
Main + battery cable goes there, and, another cable comes up from there to feed the power distribution box.

Just a suggestion.


You should see 12v on the green "excite" wire. are you sure you have continuity ? You say 2v and that is not normal


http://www.gt40s.com/forum/attachment.php?attachmentid=22883&d=1187308348

 

[primordialpaul]

Check the connection down on the starter.
Main + battery cable goes there, and, another cable comes up from there to feed the power distribution box.

Just a suggestion.


You should see 12v on the green "excite" wire. are you sure you have continuity ? You say 2v and that is not normal


http://www.gt40s.com/forum/attachment.php?attachmentid=22883&d=1187308348

I will recheck starter connection, i was told the green wire was for the charge indicator lamp as the diagram shows and it should have 2 volts or so if functioning correctly, that could be wrong, but i was also told to check if there was an open ground to run the vehicle and pull the plug from alt. If light went out it was functioning and if it stayed on it was grounding out. Mine went out. Will check voltage again.

 

[primordialpaul]

Check the connection down on the starter.
Main + battery cable goes there, and, another cable comes up from there to feed the power distribution box.

Just a suggestion.


You should see 12v on the green "excite" wire. are you sure you have continuity ? You say 2v and that is not normal


http://www.gt40s.com/forum/attachment.php?attachmentid=22883&d=1187308348

Oddly enough i have a dead cluster the green wire is getting about one volt, my fuses and battery are reading around 10 and my alt yellow wire is getting 10. I hate this damned truck..

 

[SWIGIN]

My 98 gave me similar problems when I got it. Turns out the battery ground wire must be bad even though my ends look mint.

To test this just clamp a jumper cable to the negative battery terminal and the other end to the engine. I clamped to the power steering bracket and as soon as I did I could hear the idle pick up and the motor even sounded better.

So I added a second battery ground to my EX and all has been well ever since.

 

[primordialpaul]

My 98 gave me similar problems when I got it. Turns out the battery ground wire must be bad even though my ends look mint.

To test this just clamp a jumper cable to the negative battery terminal and the other end to the engine. I clamped to the power steering bracket and as soon as I did I could hear the idle pick up and the motor even sounded better.

So I added a second battery ground to my EX and all has been well ever since.

Wish it was so, thatd be an easy enough fix but no go, cluster dim reading low volts clamped the jumpers to a few different points no change.

 

[MAS Tequila]

The green with red stripe wire needs 12 volts.

Go up to the firewall (on my 2000 5.0) or wherever your trans harness connector is, just follow the green/red wire.

Check the voltage on both sides of the connector, then take the 10mm head bolt out and separate the connector and recheck.

I ended up having to run a new wire from the firewall side to the alternator.

I had 12v on the firewall side and when connected it would drop to almost 0.

It was grounding out somewhere between the connector and alternator.

It drove me nuts also.

Just be careful there are two red with green stripe wires that are extremely easy to confuse with the exciter wire.

Just don't ask me how I know that one.

 

[primordialpaul]

The green with red stripe wire needs 12 volts.

Go up to the firewall (on my 2000 5.0) or wherever your trans harness connector is, just follow the green/red wire.

Check the voltage on both sides of the connector, then take the 10mm head bolt out and separate the connector and recheck.

I ended up having to run a new wire from the firewall side to the alternator.

I had 12v on the firewall side and when connected it would drop to almost 0.

It was grounding out somewhere between the connector and alternator.

It drove me nuts also.

Just be careful there are two red with green stripe wires that are extremely easy to confuse with the exciter wire.

Just don't ask me how I know that one.

Will do thanks. It always surprises me when any wire is run carelessly enough that it snaps breaks or chafes but ive seen it enough times i shouldnt be. Hell my 68 pontiac hasnt had any wiring done aside from grounds where the floor pan rusted but hey.. chasing wires has gotta be my least favorite thing ever to have to do on a vehicle haha..will come back with results.

 

[primordialpaul]

The green with red stripe wire needs 12 volts.

Go up to the firewall (on my 2000 5.0) or wherever your trans harness connector is, just follow the green/red wire.

Check the voltage on both sides of the connector, then take the 10mm head bolt out and separate the connector and recheck.

I ended up having to run a new wire from the firewall side to the alternator.

I had 12v on the firewall side and when connected it would drop to almost 0.

It was grounding out somewhere between the connector and alternator.

It drove me nuts also.

Just be careful there are two red with green stripe wires that are extremely easy to confuse with the exciter wire.

Just don't ask me how I know that one.

So i do have 12 v when connector is not attached to alt. Drops whwn i plug it in. Not sure what connector the trans harness connector is, top pass side of firewall? Has maybe 30 40 wires in it with a 10mm bolt holding it to fitewall? Or is it closer to distribution box in a square mounted on drivers side of engine? Is there anywhere easy for me to just cut it and run a new wire, i can already tell this is going to suck, i cant see where any of that runs without taking a bunch of stuff off and the break could be anywhere. Can i run a wire from switched power in the dist box to the alt or is there some kind of kill switch for the alternator in the dash itself?

 

[primordialpaul]

Any thoughts on this video? I dont have a test light so i cant recreate the test but is it possible im somply not getting good enough voltage to my main power wire? Again i want to confirm i should have twelve volts to the excite wire because the motorcraft forums most are saying that putting twelve votls to it will burn out my regulator and that its supposed to have a lower voltage, ive tested the lt grn red wire at the harness on the pass side of the firewall and i do only get 2v if that is supposed to have 12 does that mean my problem is between that harness and the dash? The power comes in from the ignition switch correct?

 

[MAS Tequila]

http://www.explorerforum.com/forums/index.php?threads/2nd-gen-issues-try-this-first.464701/

The 2nd picture is the connector I'm talking about.

Here's what I did:

Somewhere between the connector and the alternator my green/red wire was shorting out.

I cut the green with red stripe wire before it entered the connector on the firewall side and soldered a new wire onto it.

The new wire is run in a piece of flexible wiring conduit (?) for protection and soldered to the alternator connector (after cutting the old wire back about 2 -3 inches.

Both solder joints were covered in heat shrink tubing.

After that my alternator started putting out 14.4 volts.

If you have any questions my number is 5612103399.

 

[koda2000]

As shown in the video, your alternator has to be turned ON to work. The 2 wires on the connector shown in the video are necessary to turn the alternator ON. The green wire with the red tracer is fed by the BATT/CHG light on your dash when the ignition key is turned to the ON position and the light remains on until the engine is started and the alternator begins charging the battery. The other wire shown needs to be hot all the time. You should never see only 2V on either wire at any time. As the video shows, you can bypass the red/red 'ish wire by connecting a jumper directly to the large terminal on the back of the alternator, or directly to the positive side of the battery. The green/red wire goes from the alternator through the trans connector plug on the left side of the engine back to the BATT/CHG light.

BTW: If your BATT/CHG light bulb on the dash is burnt out, your alternator will not be turned ON when the engine starts.

As far as the tests performed in the video, test lights are very inexpensive to buy and easy to make if you have an old bulb socket (as seen in the video). VOM's are great, but as the video shows they shouldn't be the only tool in your electronic testing arsenal. Volts are one thing, but AMPS are what makes things work.

If you find either of the 2 wires in the video are not supplying power to the alternator, you can permanently jumper the red/red 'sih wire or splice in a new piece of wire before the trans plug for the green/red wire if that solves the problem.

 

[primordialpaul]

As shown in the video, your alternator has to be turned ON to work. The 2 wires on the connector shown in the video are necessary to turn the alternator ON. The green wire with the red tracer is fed by the BATT/CHG light on your dash when the ignition key is turned to the ON position and the light remains on until the engine is started and the alternator begins charging the battery. The other wire shown needs to be hot all the time. You should never see only 2V on either wire at any time. As the video shows, you can bypass the red/red 'ish wire by connecting a jumper directly to the large terminal on the back of the alternator, or directly to the positive side of the battery. The green/red wire goes from the alternator through the trans connector plug on the left side of the engine back to the BATT/CHG light.

BTW: If your BATT/CHG light bulb on the dash is burnt out, your alternator will not be turned ON when the engine starts.

As far as the tests performed in the video, test lights are very inexpensive to buy and easy to make if you have an old bulb socket (as seen in the video). VOM's are great, but as the video shows they shouldn't be the only tool in your electronic testing arsenal. Volts are one thing, but AMPS are what makes things work.

Batt light is on so i know that works, and when the plug is pulled from alt it goes off of course the truck dies shortly after. The 2v is on the red grn wire, the yellow power wire holds at whatever voltage the battery currently has. With key off or on. Also not shown in the video is that my harness has the white black external stator wire that shows no voltage regardles of key position or running engine. I really wish i could get a schematic with voltages as it really bothers me that some are saying 2v for exciter wire and you all are saying 12 and that i get 12 at the plug when not hooked up but it drops only when i plug it in.. im afraid of blowing the regulator by putting too many votls to that. All i know for sure is that ford put too many failsafes in this damned truck and an indiot light shouldnt be putting power to the charging system.. i miss the days when wiring harnesses were as simple as my 68... so! If im bypassing the grn red wire im runnig it to the longer connector on that feeds through the firewall and not to the sqaure one by the intake (4.0 motor btw) sure its a bit different from the 5.0 setup

 

[primordialpaul]

Used jumpers between power supply on back on alt to red grn wire got a big spark so i took it off immediately, used jumper between red green on connector on firewall to red grn on alt, engine slows to almost stall and keeps going, batt light stays on. Am i not understanding what i should be bypassing??

 

[primordialpaul]

And a little bg on myself, i live literally in the middle of the woods alone, i work with what i have here since without a running a truck i cant get into town to pickup tools or supplies. Upon realizing what a dilemma this is, i realize when i do(if ever) get this truck goin its time to pic up a few more thing.. all help is greatly appreciated, so thank you all.

 

[koda2000]

You got a big spark because the GRN/RED wire is the ground for the BATT light and is controlled by the alternator's voltage regulator. So what you did was basically run 12V straight to ground (big spark).

What I previously suggested is that you can try bypassing your existing GRN/RED wire between the trans plug and the alternator. If the BATT light goes off when the engine is running then the problem is being caused by the GRN/RED wire or it's connection through the trans plug. "Bypassing" the GRN/RED wire does not mean running 12v through it.

 

[primordialpaul]

You got a big spark because the GRN/RED wire is the ground for the BATT light and is controlled by the alternator's voltage regulator. So what you did was basically run 12V straight to ground (big spark).

Fair enough. Didnt realize it was a ground wire, guess its possible i fkd it up arcing it like that but when i jumped from the trans connector the batt light did not go off. if thats the case then when i use my voltmeter i should be using the ground side to the pin and the red wire to a power source to measure correct? Ive been doing it backwards or does it not matter?

 

[koda2000]

It doesn't matter which test lead you use. It will either read as a positive number or a negative number (ie 12V or -12V), but it will the same number of volts either way.

I don't know that either the GRN/RED or the red/red 'ish wires are you problem. I'm just trying to explain what the video was saying.