Can You Replace a Diode in an Alternator

It is possible to replace all the parts of the alternator, including the diodes in the rectifier plate. The only sure dead of an alternator is a breakage of the case. Even a defect in one of the windings is curable, although it requires expensive rewinding.

What happens when alternator diodes fail?

If only one or two diodes have failed, the alternator may still produce enough current to meet the vehicle’s electrical needs, but it may not be enough to keep up with higher loads or keep the battery fully charged. This could cause the battery to run down over time.

Can you repair a diode?

Diodes of can always be replaced with those of higher capacity, since a component with greater current capacity can always handle lower current. One needs to check its PIV, and sometimes the forward voltage drop.