Hi Guys. Visited many times this forum but now I need help from anyone who can. I have a 97 F250 5.4 L .Few days ago I was driving around the town and I stop to some store, when I come back my battery was drain and some nice guy give me a jump. When I get home I charge the battery and I get-it to 12.4 V ,then I start the engine and I check the alternator to see if is charging but there was 12.4 V still. I didn't get any higher than 12.4 even start to drain but very slow. I was thinking is the mega fuse and the field mini fuse but all was good. I decided to buy a new alternator and I did.
I installed the new one and same thing no charge. I send-it back the alternator thinking is bad as the guys from advance auto parts told me and I received today another one new in box. I installed few hours ago with new mega fuse and mini fuse and same thing happened no charging at all. Now I am really confused but I hope someone here in this great forum could help me to trace the problem. Just to mention all fuses and relays working good. Thank you and I appreciate any help.

 

https://www.ford-trucks.com/forums/1...g-problem.html

 

I read that before but the guy installed new alternator and all was good. On me I installed 2 new alternators and I can't believe both of them are bad .I clean all the wires connections so there is no broken or loss wires . Any way thank you for the link.

 

Is the charge lamp on?
Did you measure voltage at the large Alternator stud with engine running?
There's not much to the whole system.
Your missing it somewhere.
.
Normally when the Alternator is not charging the dash lamp is on.
Since you changed Alternator two times and replaced the fuses, it leaves the
charge lamp circuit, the plug on the Alternator or wiring or even the Battery with an open cell strap, internally.
A load test would pick up a faulty battery.
Good luck.

 

Just to be clear - charging a discharged battery up "to" 12.4 volts isn't anywhere close to a full charge. With that said it doesn't sound like the alternator is charging.

 

Thank you for your replay. My battery dash light is off and the needle on battery gauge is going up to the middle when I start the engine. I was thinking is the faulty battery but when I put the battery on the charger and then I disconnected from the charger and leave-it over night there is no discharging just 1-2 volts not completely drain. I was thinking is something I can fix by my self but as I see I have to go to some good electrician.

 

Just for clarification, how (where) are you checking the alternator output?

 

Does the "battery dash light" turn on at KOEO?

 

I put the volt meter at the battery poles as I see on videos on you tube.
The dash battery light not coming on at all.

 

I didn't see where you answered Bluegrass's question.

 

Yes I did I checked before mega fuse after mega fuse and at the Alternator stud but with the same reading on all this points no changes not even a volt or something.I did a parasitic draw test and I have 0 drainage and the battery keep the charge. I am sick of it I run out all the options except to take-it to the shop.

 

I'm not sure I understand your response.
If the mega fuse is good and wire is good you have to read the battery voltage at the heavy stud on the alternator.
Are you saying you do not read any voltage?
If no voltage the circuit is open.
If yes voltage is there, the circuit is complete.
.
My concern is no charge lamp is On at the dash, if I read you correctly.
That means the lamp circuit is open.
.
Follow this closely as to what the lamp circuit is and how it works.
A 'fused' supply is present on the ignition switch.
When you turn the ignition on, the circuit completes through the dash lamp to the alternator plug and to the Alternator regulator.
The regulator supplies a ground to light the dash lamp.
After starting, the Alternator output rises and is detected by the regulator.
The regulator 'opens' ground to the lamp circuit putting the lamp out.
This is normally how you are alerted to the general health of the system.
.
If the dash lamp is not On 'and' there is no charging, running or not, that is an issue to address and may be part or all the problem.
Be sure the plug on the Alternator is fault free.
With info as it is now, that's all I can offer.
Most of the problem is understanding how the system works then solving for the issue.
.
Once the system is charging, you should see the voltage rise after cranking/starting as the Alternator restores the charge to the battery.
It can go as high as 15 volts initially then taper back to 14 as the battery recovers. All dependent on the health of the battery.
12 to 12.2 volts is normal after the battery sets for a half hour after shut down and not a valuable indicator of charge issues, otherwise..
.
How does the regulator work?
The regulator has a voltage reference built in to compare the battery voltage to the reference value. The difference between the two values controls the charge rate back to the battery.
As the battery voltage rises toward the regulator reference value, the charge current is reduced by the regulator control of the alternator field winding supply.
Sorry if it sounds a bit complicated but you have to work with the system as it is designed or have a good shop do the work.



Good luck.

 

Check fuse 19 in the junction box. If that fuse is open or the charge indicator lamp is open the regulator will not excite the alternator field windings.

 

Today I turn the ignition on to see if the battery lamp goes on and there was no light coming on. I take out the cluster to see if the actual bulb is blown but everything was OK the bulb was OK. I put-it back and try again the battery light still not coming on. Do you know if that lamp is connected to some fuse and which one because all the fuses are OK, maybe I miss something here. I try to understand how all this charging system works but I don't see where is the missing point on my case.
About fuse 16 everything is OK in my diagram says that fuse is controlling the "Trailer tow battery charge and stop/turn lights" and all works.
To answer to the previous question at the alternator stud I have same reading as at the battery poles when engine running.
The only thing I think now is why the battery lamp do not light up when I turn the ignition on as you guys say it should.
Thank you for all the replay's and I will let you know if I will find something.

 

Today I found the problem it was really a challenge for me I took out the fuse box from inside driver side and I check all the wires.I found on fuse 19 one side of the pin of the fuse didn't touch the wire the wire was out of the enclosure I guess when I push the fuse I push the wire connector terminal out. I remember some of my fuses I have to bend the terminals a little bit to stay secure in place and maybe on this I went to far and the fuse push the terminal out. I am glad I found this problem because I was going crazy not knowing what is going on. When I check the fuse before I have power in both terminals but was only because the fuse has a continuity.
Thank you all for your replays and help. GOD bless.