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Diode Assembly

  1. Place ohmmeter scale on x100 scale. Connect ohmmeter leads across "B+" terminal and 3 stator terminals one at a time. Reverse leads. Ohmmeter should indicate continuity in one direction only.
  2. Connect ohmmeter leads across negative plate and 3 stator terminals one at a time. See Fig 1. Reverse leads. Ohmmeter should indicate continuity in one direction only.
  3. Connect ohmmeter leads across "D+" terminal and 3 stator terminals one at a time. Reverse leads. Ohmmeter should indicate continuity in one direction only. If diodes are found to be defective, replace diode assembly.
Fig 1: Typical Bosch Diode Assembly Test
G29438Courtesy of BMW OF NORTH AMERICA, INC.