Had to replace failed alternator. Mechan-x installed a rebuilt. After a few miles alternator idiot light came on - but false. Still charging OK. Tried another rebuilt - same problem. Light is on after several months but alternator is still charging fine - hence black tape over the dash light. What is the cause of this false positive? How to fix? Mechan-x assures all wiring properly connected.
There’s a wire from the “neutral” line of the alternator to the dash light circuit.
That line might have been damaged when the alternator was replaced.
+1 …start wiggling some of the connectors on the alt itself. You’ll find the one that was cracked or whatever when MechanicX installed the alt.