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2004 ford f150 charging system


Old 01-05-2008, 11:50 PM
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2004 ford f150 charging system

has anybody have any issuse with the charging system light staying on after you have changed the alternator.

Story - the factory original alternator went out last friday night, on saturday replaced the alternator. voltage and battery check out fine charge light still on. replaced the alternator thinking that the one i purchased was bad off of the shelf. charge light still on. took to mechanic he checked the battery and alternator no issuse that he could find. charge light still on. took it to dealer no. 1 he said that the connector on the wiring harness at the alternator was bad and replaced it. charge light still on told me not to worry about it the system is fine. the response pissed me off took the truck to my local mechanic he went through the truck looking for shorts or blown fuses. He found nothing wrong he thought that maybe the pcm was bad and told me to take it to the dealer and have him flash the pcm to see if that would fix the problem. so off i go to dealer no. 2 - he flashes the pcm, this does not fix the problem. he says that the alternator that I put on is the wrong alternator. I don't think that is the problem but agree to let them put a new motorcraft on the truck to see if that fixes the problem (both of the alternators that I have put are motorcraft). low and behold this didn't fix the problem.

has anybody else had this problem? I am at my witts end on this. the NHTSA has 3 tsb's regarding the charging system and the indicator light on the dash. the only thing they show in the files are a summary no description of how to fix the problem. ford does not reference these three tsb's in any of the sites that I or the dealers or mechanics can access.

does anybody have a solution?
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Old 01-06-2008, 10:57 PM
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Join Date: Jul 2004
Location: Easton, Pa.
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I don't have the specific charge circuit for your year but usually the charge lamp is powered thru the ignition switch.
The alternator regulator controls the ground back to the charge lamp.
When the alternator comes up to operating level, the regulator senses this and remove ground from the charge lamp putting it out.
Since you have replaced 2 alternators and their built-in regulators, I have to feel there is a ground on your lamp lead outside the alternator plug up.
I would make a resistance measurement from the lamp lead to ground, off the alternator with the plug off the alternator and the ignition switch 'off' to see if there is a ground completeing the lamp circuit, on a hard ground basis and keeping the lamp lighted as long as the ignition switch is on and supplying power to the lamp from that end.
This would not really interfere with alternator or charging operations, otherwise.
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Old 01-26-2010, 01:48 PM
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Did you ever get that indicator light to go off? Just curious, I'm having the same issues
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Old 08-15-2011, 04:23 PM
Join Date: Aug 2008
Location: N. CAL.
Posts: 12
I'm having the same issue!

does anybody have a solution?
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Old 08-15-2011, 06:53 PM
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Originally Posted by F150INN View Post
does anybody have a solution?
You have the same problem, or the similar symptoms ?
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