The diodes are the electronic part of the alternator that convert AC voltage to DC. Switch your multimeter to the lowest AC setting and reattach the test leads to the battery.

We're going to answer all your questions about alternator replacement, repair, and the cost involved to do it yourself or have a pro handle it.

When they were done with our alternator it had been disassembled, cleaned, equipped with new bearings, brushes, diodes and an upgraded stator to increase the output to 90 amps.