Ford Fiesta mk7 diesel not charging

[Hairymelon]

Charge light comes on when key turned and goes out when engine runs , but battery is not being charged. Any ideas ?

 

[Burnerman]

The charging lamp isn't actually an indication of the alternator output, believe it or not.....you need to test the voltage at the battery with a multimeter and you're looking out for around 14.5v.
John

 

[Hairymelon]

Thanks John , I have done that and with the engine running the voltage is 12.4 , engine off 12.8 , so no charge. Recently the car had a bust coolant hose and may have got quite hot but I don’t think that’s relevant really

 

[Burnerman]

I guess the only thing you can do is to check the electrical connections into the back of the alternator for cleanliness and security.
It's unlikely that a water deluge would have caused any harm.
John

 

[thomp1983]

This possubly has the stupid smart charge setup manufacturers insist on using, unplug the small wiring plug on the alternator and measure the voltage again at the battery when running to see if it's increased.

 

[Mottie]

I has this on a Focus once but the light worked as normal for 1 minute or so and then stayed on. Turned out it was a 1 amp fuse blown in the fuse box.