Rotor Circuit Test
- Remove rotor from alternator. Set ohmmeter to X1 range. Measure resistance between rotor slip rings. Resistance should be 2.0-3.9 ohms. Higher resistance indicates damaged slip ring solder connection or broken wire.
- Lower resistance indicates shorted wire or slip ring. Replace rotor if damaged. Connect one ohmmeter probe to either slip ring. Connect other ohmmeter probe to rotor shaft. Resistance other than infinite indicates rotor is shorted to shaft. Replace rotor if shorted.