Have Ford Questions? Ask a Mechanic for Answers ASAP
Hello and welcome!My name isCustomerand I can assist you with your question.
I will try my best to answer all of your questions.
However, before we get started, please let me mention a few things.
1. If at any point you would like to speak on the phone, please feel free to request a phone call on your end and I can call you right away.
2. If you dont understand any technical terms or anything that I mention (component tests or theory or operation), please let me know and I will provide you with a more in debt explanation or answer.
3. Please understand that I am here to help you anyway I can.
Your saying the battery and alternator test out good but the charging light remains illuminated on the cluster? Is that correct?
Are there any codes in the computer?
Can I get your VIN and the code number in the computer?
Thank you for that information.
Was this light illuminated before the alternator was replaced?
Where was the alternator purchased from?
Thank you for that information. This battery or charge indicator light is on either because of a bad new alternator or a wiring issue between the PCM and alternator. I would replace the alternator with one from the dealership first and see if that does the trick. If not, then check the wiring to and from the alternator.
Or you can check the wiring to and from the alternator first if you would like. Would you like some info on how to do this?
Because I have seen aftermarket alternators cause the charge indictor light to come on or illuminate on the dash even if they are still charging the battery
A wiring issue going to the alternator or a faulty new alternator
The PCM expects a very specific response on the monitor circuit, it is very important to install an alternator that meets or exceeds factory specifications.
Here is how to check the wiring to the alternator.
The GEN-COM (generator command) signal from the PCM to the alternator. If there is a change in the vehicle's electrical load, such as turning the headlights on or off, a series of rapid battery voltage pulses should normally be seen on this circuit. This is feedback signal from the voltage regulator to the PCM, and is called the GEN-MON (generator monitor) signal. If the GEN-COM signal is OK, but there is no GEN-MON signal from the alternator, disconnect the voltage regulator, and with the key on, check for more than 8 volts on the wire, coming from the PCM. If OK, replace the alternator, making sure to get the correct one for this PCM-controlled system.
Here is a wiring diagram of this circuit.
I am glad I can help!
It has been a pleasure working with you. Please dont forget to honor your good faith deposit by rating my answer as "5 STAR SERVICE" for assisting you today.
Keep in mind, we can still continue this conversation at no further cost to you even after you rate my answer. Just reply back to me using this page and I will get it and get back to you ASAP!
Also, if you are a member or if you have a subscription to the site, you still need to rate my answer in order for me to get credit for assisting you with your question.
Please let me know if you have any further questions.