Amp turns off... still

[metalheadjoe 10+ year member]

The oem is broke unfortunately, ill look to testing. Do they need the alternator out to test?

I've always taken it out. They connect it to a machine in the store that spins it.

 

[AnthonyO 10+ year member]

No. Corroded wires don't increase voltage. If they did, we'd all run corroded wires to our amps to keep our voltage up.

But if he has corroded terminals that are making intermittent contact, he could get voltage spikes. I know you want him to go and get the alternator tested.

 

[metalheadjoe 10+ year member]

But if he has corroded terminals that are making intermittent contact, he could get voltage spikes. I know you want him to go and get the alternator tested.

That could cause intermittent voltage drops, but not spikes. Many electronics on your vehicle are an intermittent load, such as windows, locks, horn, blower motor, you get the idea. If intermittent loads caused electrical issues, it would affect new vehicles.

 

[Buck 5,000+ posts]

That could cause intermittent voltage drops, but not spikes. Many electronics on your vehicle are an intermittent load, such as windows, locks, horn, blower motor, you get the idea. If intermittent loads caused electrical issues, it would affect new vehicles.

x2, I've never seen a corroded terminal cause a voltage spike. More resistance = lower voltage.

 

[AnthonyO 10+ year member]

Okay. Finally found one person with a 2006 F150 with the same issues. He tried four different alternators
This was recommended
You may have a bad connection in the plug-in connector...or there may be a fatique separation somewhere inside that wire. From your symptoms, that 'signal' is not getting fed back to the alternator continually, so it isn't getting the correct signal on when to charge and when NOT to charge.

He change the connector at the alternator and it fixed his problem.

 

[metalheadjoe 10+ year member]

Okay. Finally found one person with a 2006 F150 with the same issues. He tried four different alternators
This was recommended
You may have a bad connection in the plug-in connector...or there may be a fatique separation somewhere inside that wire. From your symptoms, that 'signal' is not getting fed back to the alternator continually, so it isn't getting the correct signal on when to charge and when NOT to charge.

He change the connector at the alternator and it fixed his problem.

Thanks for taking time to do the research. What years did that affect? Was it limited to F150's or to 5.4's?

 

[AnthonyO 10+ year member]

Thanks for taking time to do the research. What years did that affect? Was it limited to F150's or to 5.4's?

From what I saw 2006 - 2008 5.4 was the only ones I could find. Most of the threads I read, no one ever fixed the problem. Or at least never reported back. And some were told by Ford that their battery was the problem. But new battery never fixed the problem, of course.

 

[AnthonyO 10+ year member]

There was one guy that was talking about a grey effect test. Using a test light on the alternator plugs. Plugged in to the exciter wire. Crank the vehicle and test light should go out and then come back on. Then wiggle the connector and or wires to see if the light goes out. If the light goes out voila. Apparently, that’s how the guy figured out his problem.

 

[AnthonyO 10+ year member]

Thanks for taking time to do the research. What years did that affect? Was it limited to F150's or to 5.4's?

I think his problem bothered me more than the op. When I typed in F150 voltage spike and saw all the threads I was like holy shit.

 

[AnthonyO 10+ year member]

Like this one. He changed a cracked plug and it didn’t fix it. But look what did


I have a 2004 XLT with the 5.4

A year or so ago, my dash light came on and I decided thatit was probably my alternator.

So I went to the official ford parts website and they hadtwo options. They had a 110 amp optionand a 130 amp option.

My window sticker (which I still have) clearly says 130 amp alternator

So I went to my dealer (didnt order it from the website)and asked them. They said the only option for my truck is a 110-amp reman from motorcraft.

I showed them my window sticker and I showed them the ford parts website (remember this is the actual ford parts website.. not someone else).

The dealer parts guys were curious. They called ford. Ford says use the 110 amp. At this point, I could have gone two ways. I knew if I got the 110 I would wonder, so I rolled the dice and got the 130 amp motorcraft reman.

It fit fine and the voltage was fine. But the red battery dash light was on andstayed on. Something was wrong.

I took it to autozone to have them check it. Their meter said the voltage regulator was bad.

So I went back to the dealer parts department and they were very cool. They gave me another motorcraft reman 130-amp alternator.

Same thing. The voltage was fine but the dash light stayed on. I took it to autozone and the charging system checked out fine.

The connector on the wire to the alternator was cracked, soI changed the wire harness from the alternator to the battery (although the crack was small and seemed unlikely to matter).

Nothing changed. The dash light stayed on and the voltage was fine.

So I went back to the dealer and got the 110 amp motorcraft reman. (which I had to buy... not complaining tho)

And that did it. The voltage was fine and the dash light was not on.

 

[metalheadjoe 10+ year member]

Like this one. He changed a cracked plug and it didn’t fix it. But look what did


I have a 2004 XLT with the 5.4

A year or so ago, my dash light came on and I decided thatit was probably my alternator.

So I went to the official ford parts website and they hadtwo options. They had a 110 amp optionand a 130 amp option.

My window sticker (which I still have) clearly says 130 amp alternator

So I went to my dealer (didnt order it from the website)and asked them. They said the only option for my truck is a 110-amp reman from motorcraft.

I showed them my window sticker and I showed them the ford parts website (remember this is the actual ford parts website.. not someone else).

The dealer parts guys were curious. They called ford. Ford says use the 110 amp. At this point, I could have gone two ways. I knew if I got the 110 I would wonder, so I rolled the dice and got the 130 amp motorcraft reman.

It fit fine and the voltage was fine. But the red battery dash light was on andstayed on. Something was wrong.

I took it to autozone to have them check it. Their meter said the voltage regulator was bad.

So I went back to the dealer parts department and they were very cool. They gave me another motorcraft reman 130-amp alternator.

Same thing. The voltage was fine but the dash light stayed on. I took it to autozone and the charging system checked out fine.

The connector on the wire to the alternator was cracked, soI changed the wire harness from the alternator to the battery (although the crack was small and seemed unlikely to matter).

Nothing changed. The dash light stayed on and the voltage was fine.

So I went back to the dealer and got the 110 amp motorcraft reman. (which I had to buy... not complaining tho)

And that did it. The voltage was fine and the dash light was not on.

Please post a picture of your pickup. I ised to own a blue 2004.

 

[AnthonyO 10+ year member]

Please post a picture of your pickup. I ised to own a blue 2004.

Oh, I do not and will not own a Found On Road Dead. Last one I owned had so much blow by it could blow up balloons

 

[Spazz131]

So I think the next steps for me are checking the alternator wires all around.

Than I may try replacing just the voltage regulator

And last I guess a new alternator again... would ordering a mechman be worth it?

 

[AnthonyO 10+ year member]

Try the grey effect test.

Plug in a test light to the far left wire on the plug. Should be brown I believe. This should be your exciter wire.
Crank the vehicle. It should stay solid as long as the car is running.
Wiggle the plug
Wiggle the wires

If the light goes out, bad plug.

 

[Spazz131]

Try the grey effect test.

Plug in a test light to the far left wire on the plug. Should be brown I believe. This should be your exciter wire.
Crank the vehicle. It should stay solid as long as the car is running.
Wiggle the plug
Wiggle the wires

If the light goes out, bad plug.

On the alternator correct