Confusing electrical issue

[Nathaniel]

I have a 2003 Ford Expedition with a weird electrical issue.
I don't know if it's my alternator or not but I'm trying to figure it out that's why I'm here to see if anybody can help me.
I was driving and my battery light came on but the battery wasn't draining it was actually looking like the charge was increasing to the battery. Then when the battery light goes off the engine is running off of straight battery power and starts draining the battery. It will get to the point where everything electrical in the vehicle will turn off one by one starting with the radio then the dashboard then the lights everything will just start turning off one by one. Then if I turn the vehicle off and try to start it again the battery doesn't have enough power to restart the vehicle. Then if I let the vehicle sit for a couple of hours it'll start up again.
The weird thing is as long as my battery light is on it will not drain but soon as the battery light goes off the battery starts to drain so the light is actually doing the opposite of what it's supposed to be doing. So is this really an alternator issue or a battery issue or an electrical wire issue? I did take my battery to be checked and they said my battery is perfectly fine. Now when my battery is fully charged it will run for as long as the battery light is on. Soon as the battery light goes out it starts to drain. I have changed my fuse box due to a fuel relay issue. So can this be a fuse issue?
Please help love my truck but I'm seriously thinking I'm getting a Chevy.

 

[stamp11127]

Did this start when the fuse box was changed?
Where did you get the replacement fuse box?

 

[Nathaniel]

It did start about 2-3 weeks after the fuse box was changed. I got a used fuse box from a wrecked vehicle of the same year online from eBay motors.

 

[Plati]

Theres a lot of ideas in this thread.
https://www.2carpros.com/questions/ford-expedition-ford-expedition-check-charging-system-light

It requires diagnosis (as you know) ... no easy answer here
I'd look at connectors for melting and the fusible link?

I have a 2003 and I cant really tell what you mean by battery light and some other statements
I know theres a guage and also the battery symbol which indicates charging problem

 

[Nathaniel]

The fusible link was loose and I had to tighten it up and I had to make sure it was on just right or the engine wouldn't start but even after that it still having the same issue.

 

[Plati]

The fusible link was loose and I had to tighten it up and I had to make sure it was on just right or the engine wouldn't start but even after that it still having the same issue.

I think you have to check the DC resistance (ohms), has to be zero. I gotta admit I dont really know but thats what I think. Can measure voltages also?

 

[stamp11127]

Check this link on how alternators work then start the diagnostic process.

http://www.expeditionforum.com/threads/alternators.29995/

 

[2003 Ford Expedit]

Did this start when the fuse box was changed?
Where did you get the replacement fuse box?

I have the same problem. I replaced the alternator I replaced the serpentine belt I replaced the serpentine belt tensioner I just got a brand new battery for the second time and it's still draining the battery check charging light check charging system late and battery light are still on right in fact got a used box from a junkyard as well and the problem started immediately after installing it and I checked the number 9 fuse in the used fuse box which is the alternator fuse and it seemed to be sloppy and loose. I am going to order a new fuse box and see if that works I'm just wondering how the fusible link works as well the reason I change the fuse box to begin with was I was told that my truck needed a new fuel pump and fuel filter because it wasn't getting any gas but I did some research on the internet and found out that it's not the fuel pump and fuel filter that it is in fact the fuse box which has an internal relay built into it so you can't change the relay for the fuel pump you have to change the whole box and I made the mistake of buying a used one from a junkyard and I've had nothing but problems since. I even tested the old alternator out of the truck at O'Reilly Auto Parts and it said the old alternator was good now I'm pissed LOL but determined to fix this being only paid $1,000 for the truck sure beats having a $800 a month car payment LOL

 

[Hamfisted]

I have the same problem. I replaced the alternator I replaced the serpentine belt I replaced the serpentine belt tensioner I just got a brand new battery for the second time and it's still draining the battery check charging light check charging system late and battery light are still on right in fact got a used box from a junkyard as well and the problem started immediately after installing it and I checked the number 9 fuse in the used fuse box which is the alternator fuse and it seemed to be sloppy and loose. I am going to order a new fuse box and see if that works I'm just wondering how the fusible link works as well the reason I change the fuse box to begin with was I was told that my truck needed a new fuel pump and fuel filter because it wasn't getting any gas but I did some research on the internet and found out that it's not the fuel pump and fuel filter that it is in fact the fuse box which has an internal relay built into it so you can't change the relay for the fuel pump you have to change the whole box and I made the mistake of buying a used one from a junkyard and I've had nothing but problems since. I even tested the old alternator out of the truck at O'Reilly Auto Parts and it said the old alternator was good now I'm pissed LOL but determined to fix this being only paid $1,000 for the truck sure beats having a $800 a month car payment LOL

You can't just pull a junkyard fusebox out and use it. The fuseboxes are unique to each vehicle as far as date of manufacture and accessories / options. If you still have your old fusebox and everything else except the fuel pump worked fine with it, you can either send it out to be repaired for about $100 or you can order a brand new fusebox specific to your date of manufacture from Tasca parts or Ford Parts Giant online for about $400. Other than that you're wasting your time.




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