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Field Open Or Short Circuit Test

  1. Perform test before alternator disassembly. Adjust ohmmeter to the x1 scale. Place ohmmeter probe on alternator "FLD" terminal. Place remaining ohmmeter probe on alternator "GRD" terminal.
  2. Rotate alternator pulley and note reading. Ohmmeter reading should be between 2.4 and 100 ohms. Reading should fluctuate while pulley is spinning.
  3. Infinite reading indicates open brush lead, damaged brushes or bad rotor assembly. Check for grounded brush assembly, grounded field terminal, or defective rotor if ohmmeter reading is less than 2.4 ohms.
CAUTION: Digital ohmmeters can not be used to perform following test procedure.
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