In this video I have a quick look at a Ford Fiesta from the used car guy that has the battery light on but appears that the alternator is still working. It is a PCM controlled charging system so let's have a look. -Enjoy!
If an SMA Video has helped you out please consider giving using "Patreon" to help support us. The videos take real time to create and pull us away from real work that pays our bills. CLICK HERE: https://www.patreon.com/southmainauto
CHECK OUT OUR "SMA SWAG" STORE! Go on Teespring and get your very own SMA merch!
https://teespring.com/stores/the-sma-store
If you don't like Patreon feel free to use the "PayPal Me" link: https://www.paypal.me/SouthMainAuto
The South Main Auto Amazon Store:
https://www.amazon.com/shop/southmainautorepairavoca
AES Wave Automotive Diagnostic Tools: https://www.aeswave.com/cart.php?m=affiliate_go&affiliateID=2525b91fc8e906e8215984074c9d9e8f&go=https://www.aeswave.com/Miscellaneous-p9347.html
Thank you for all the continuing support!
--Eric & Vanessa O.
Feel like sending some swag to SMA because you love the videos but don't know where to send it?
Just ship it here:
South Main Auto Repair
47 S. Main St
PO Box 471
Avoca, NY 14809
Disclaimer:
Due to factors beyond the control of South Main Auto Repair, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. South Main Auto Repair assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. South Main Auto Repair recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of South Main Auto Repair, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained.

50 thoughts on “Ford fiesta: battery light on”
  1. Avataaar/Circle Created with python_avatars Ayham Mansi says:

    My friend if you can help me
    I have ford expedition 08 battery warning light comes on and off . Scanner shows rapid fluctuation in voltage reading between 6 or 7 volts to 16 or 17 volts .
    Keeps playing in between . What do you think 🤔

  2. Avataaar/Circle Created with python_avatars selvam G says:

    Hi you could have established differences between defect and new alternator through LIN signal differences

  3. Avataaar/Circle Created with python_avatars danimardani says:

    By unfortune, he didn't fix anything, he just "swaped" an alternator. Anyone could do that , but a real master could tell us where from the problem comes. I have a Fiesta with same problem and not gonna pay for a new alternator if the old one is still charging..

  4. Avataaar/Circle Created with python_avatars Subjohny says:

    so..it was alternator?

  5. Avataaar/Circle Created with python_avatars liberty bangaro says:

    Why is battery light on yet I changed alternator

  6. Avataaar/Circle Created with python_avatars Louis Sparks says:

    I wanted to see Mr. O replace the alternator; I may have to replace the one on my 2011 Fiesta.

  7. Avataaar/Circle Created with python_avatars lonewolfsstuck says:

    this is useful for if/when mine does this. Purchased mine recently.

  8. Avataaar/Circle Created with python_avatars Doug Elliott says:

    Thank you for doing these videos they are great. You’d be my mechanic if you were close

  9. Avataaar/Circle Created with python_avatars Hypa Harry says:

    gotta hit 88mph not 87mph. Great vid as always

  10. Avataaar/Circle Created with python_avatars N K says:

    If this was not fixed what problem would it create?
    Over charging the battery?

  11. Avataaar/Circle Created with python_avatars Juan Rios says:

    you didn't show the test points and going to fast not intend to show any thing !!!!

  12. Avataaar/Circle Created with python_avatars Dario DCA Ltd says:

    I had exactly the same fault code U0120:00-6c no comms with generator on a 2013 Ford Transit van with the same system single wire LIN control, I done exactly the same tests you have volt drop pos to pos and volt drop ground to ground, scoped the LIN signal 0-12v square wave and advised the garage to replace the alternator. They fitted a genuine Ford alternator and they called me to say the same fault and battery light have came back on.

  13. Avataaar/Circle Created with python_avatars No Name says:

    Amen! Just wait till you see 2021…

  14. Avataaar/Circle Created with python_avatars Kridder Fur says:

    Good stuff but – Electrically challenged here. Wouldn’t you want to measure current from the alternator? Not sure why a voltage is held across an alternator.

  15. Avataaar/Circle Created with python_avatars Patrick Milligan says:

    Oh Tommy Boy! LMAO!

  16. Avataaar/Circle Created with python_avatars MCosmin says:

    can someone explain what voltage drop is ? i cant get my head around it. seriously.

  17. Avataaar/Circle Created with python_avatars ryan s says:

    I wonder if this was bench tested at a not a sponsor parts store would the alternator pass

  18. Avataaar/Circle Created with python_avatars John B says:

    Where did you get the orange scope????

  19. Avataaar/Circle Created with python_avatars flnthrn2 says:

    The problem you got here is that you're trying to have a conversation with an alternator in the first place.

  20. Avataaar/Circle Created with python_avatars Mohamed Ahmed says:

    Love Back to Future reference.
    And 2011 was a pretty good year, the best in my life.

  21. Avataaar/Circle Created with python_avatars Third Car Garage says:

    Amen

  22. Avataaar/Circle Created with python_avatars systemloc says:

    'I could take a dump in a box and put a warranty on it… I have spare time!'

  23. Avataaar/Circle Created with python_avatars Stephen Ufkin says:

    Good video but my question is, why was the battery at 11.5v if the alternator was charging at 14.3v? I was an electronic tech many moons ago and I understand your troubleshooting technique, but my first instinct would have been bad battery if it were that low and I got 14.3v off the alt.

  24. Avataaar/Circle Created with python_avatars Patrick Ritenour says:

    I miss the days of 1 wire, self exciting gm alternators…

  25. Avataaar/Circle Created with python_avatars William Whitman says:

    Like most sold used cars, that turd is out of gas. Part of the formula for keeping the profit margins near the maximum allowable wallet suction value.

  26. Avataaar/Circle Created with python_avatars A Father To The Fatherless says:

    I don't get it. It was charging fine and tested fine, but it still needed replacing??? What led you to replace it if all the testing turned out fine?

  27. Avataaar/Circle Created with python_avatars tj2040168 says:

    I wanna see more of that uScope

  28. Avataaar/Circle Created with python_avatars Jordon Ambrosier says:

    If it was mine I would have just waited for it to really quit.

  29. Avataaar/Circle Created with python_avatars Jason Albright says:

    Tommy Boy. Hell yeah. Great video as always.

  30. Avataaar/Circle Created with python_avatars MIKE CONT says:

    Very informative…as always. Great video sir

  31. Avataaar/Circle Created with python_avatars Sholdon Fenech says:

    I done one under warranty before, similar issue but intermittent. Turned out to be the pulley on the alternator.

  32. Avataaar/Circle Created with python_avatars pokey999991 says:

    That’s. 88 mPH to go BACK!

  33. Avataaar/Circle Created with python_avatars Mr Peabody says:

    survey says oops shitty connection! thats why i love sma

  34. Avataaar/Circle Created with python_avatars JAXTRUX says:

    Amen

  35. Avataaar/Circle Created with python_avatars Vic Koenning says:

    Syth

  36. Avataaar/Circle Created with python_avatars Neil Lawrence says:

    Left over nut and lockwasher laying on the cowl?

  37. Avataaar/Circle Created with python_avatars omegaman55 says:

    Eric i've been gone for a while .but congrats on 500K. I'm a long time subscriber

  38. Avataaar/Circle Created with python_avatars Eduardo Rivera says:

    Wish I had that kind of extra time in my shop to diagnose and then go back and record the diagnose again lol..we do gas and diesel we test not guess just incase..and those hater a welcome to criticism that tell me u like to guess 😆 like I said busy shop here gotta go..

  39. Avataaar/Circle Created with python_avatars Joe Plourde says:

    Gone

  40. Avataaar/Circle Created with python_avatars Joe Plourde says:

    Joe

  41. Avataaar/Circle Created with python_avatars Joe Plourde says:

    Please be real with me

  42. Avataaar/Circle Created with python_avatars Ganesh Narayan says:

    Great video Mr O. just wanted to ask you does the pcm really askes the alternator let's go for lunch.

  43. Avataaar/Circle Created with python_avatars John B says:

    What is the orange scope your using…

  44. Avataaar/Circle Created with python_avatars J S says:

    Coolant level is low, the old alternator didnt like that… 🙂

  45. Avataaar/Circle Created with python_avatars robinsonsauto says:

    Nice fix Eric! Did you happen to see the process data prior to replacing the alt. Desired vs actual?

  46. Avataaar/Circle Created with python_avatars John Bickle says:

    so would giving another car a jump start with your engine running be a big no no as charging voltage could get silly ????????????

  47. Avataaar/Circle Created with python_avatars Sammy Molina says:

    Amen 2020 to 2011

  48. Avataaar/Circle Created with python_avatars Andy Alfaro says:

    Amen brother

  49. Avataaar/Circle Created with python_avatars Bill Clayton says:

    AMEN

  50. Avataaar/Circle Created with python_avatars Paul Fiebke says:

    What was the small metor name and around what does it cost? Keep up the good work

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.