Very strange PDC problem

[TerminatorX5]

the light in the cluster for the battery is staying dark when the diode bridge on the voltage regulator from the alternator is working fine. when one of the diodes is going south, due to whatever factors (age, heat, too much juice...) the balance of the bridge is disturbed, and the light illuminates.

I do not know if the bridge or the regulator are repairable/replaceable individually, but that is a sign of the alternator... also, the electrical gremlins will manifest when the voltage is too high - it is just more common to see voltage too low, as in failing batteries, than to see voltage too high...