my alternator light has decided to come on despite the fact that the car is registering 13.8v when running vs 12.2v when not running. to my simple mind it is therefore charging so why has the light come on, any bright sparks out there? Mark

had something similar, fitted an extra earth strap from block to chassis - seemed to work.
worth checking your earth strap in case its worked loose????

nope that's not it but thanks for the suggestion