FixVault

Rotor Test

  1. Using an ohmmeter, measure resistance between rotor and slip rings. See Fig 1 (STEP 1). If continuity exists, replace rotor.
  2. Measure resistance between slip rings. See Fig 1 (STEP 2). If resistance is not 2.8-3.0 ohms, replace rotor.
Fig 1: Testing Alternator Rotor (Nippondenso Shown, Mitsubishi Similar)
G91H02012Courtesy of GENERAL MOTORS CORP.