Alternator Rectifier Diode Plate Assembly, Diodes, Rectifier Cover, Plastic SRE Cover, and Diode Sets. Hint: if you have the # from the manufacturer tag on your alternator, use it in the gold search bar above and many materials including rectifier should list on the search page. AND/OR contact us for quick help too
Rectifier By Alternator Manufacturer
Why does the Rectifier Diode Fail?
The number one cause for Diode failure is continued driving with a weak battery that is no longer holding charge or not holding 100 State of charge.
Poor battery condition causes the alternator to work at high to excessive capacities for extended times. Alternators are not designed to run at max capacities or more for extended time.
The diodes can be damaged in this condition. Almost anything electrical can be damaged with the heat this scenario causes; Bad cables, added accessories, failing electrical components can all mimic the same condition of a failing battery causing excessive load diode damage.
How to Test The Rectifier / Diodes on the Car
A bad alternator diode will cause A/C Voltage reading at the Battery. Some reasons to check this is if your headlights or instrument panel lights are flickering or dimming and, if additional fail lights like ABS along with Battery light are illuminating can be all to a bad diode(s).
* To check for a possible bad alternator diode, switch your voltmeter to a low setting on the AC (alternating current) voltage scale.
* With the engine running, touch the meter probes to the battery terminals.
* Your voltmeter should read 0 AC volts.
Any amount of AC voltage would indicate a bad diode, so you'll need to replace the alternator.