2003 Ford Fiesta 1.4 battery light is on

Discussion in 'Car Repairs / Maintenance' started by alan666, 14 Apr 2010.

  1. alan666

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    The battery light on a 1.4 2003 Fiesta is on constantly. When I put the battery on a battery charger/conditioner, it reported the battery was poor or sulphated and couldn't be recovered so I replaced it but the battery light is still on. I have checked voltages and the alternator was not charging so I removed the smart charge plug and it charges at 14v. I have read elsewhere that pin 3 on the Focus smart charger plug should be at the same voltage as the battery as it is a reference voltage. Don't know if it is the same on the Fiesta so I checked, but I wasn't sure which was pin 1 and which pin 3. One has around 4v the other 8v so neither has 12v. Any ideas what else I could check?
     
  2. ^neo^

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    sounds like the voltage regulator in the alt has died.
     
  3. Spark123

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    Is it a silver calcium type battery? What type did you replace it with?
     
  4. diydazzler

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    Put a volt meter across the battery with the engine running and you should see around 14 volts.
    If its less ie 12v then the alternator needs looking at
     
  5. alan666

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    It is an AC Delco Calcium battery. With the 3 pin plug disconnected from the alternator there is over 14v measured accross the battery so the alternator is charging as it should but when the plug is reconnected, it stops charging. So the problem is somewhere with the smart charging circuit.
     
  6. Burnerman

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    Ye gods and this is what Ford call progress.....
    They developed smart charging to cope with the new calcium batteries. This effectively boosted the charging voltage to around 15v - but it was controlled by the cars ECU - not by the alternator.
    Removing the smart charge plug allows the alternator voltage regulator to take over and the battery will still be charged - although the battery light may still be on.
    Check the wiring condition as it leaves the smart charge plug - if one conductor is broken, frayed or burnt you get your symptoms.
    (I got this from a Transit TSB by the way...it may apply to yours).
    Hope this helps!
    John :)
     

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