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Power Transistor Test

  1. Remove the passenger's dashboard undercover (see PASSENGER'S DASHBOARD UNDERCOVER REMOVAL/INSTALLATION ).
  2. Disconnect the 4P connector from the power transistor.
  3. Measure the resistance between terminals No. 3 and No. 4 of the power transistor. It should be about 1.5 kΩ.
    • If the resistance is within the specifications, go to step 4.
    • If the resistance is not within the specifications, replace the power transistor.
    NOTE: Also check the blower motor. Power transistor failure can be caused by a defective blower motor.
    Fig 1: Measuring Resistance Between Power Transistor Terminals No. 3 And No. 4
    G08094380Courtesy of AMERICAN HONDA MOTOR CO., INC.
  4. Carefully release the lock tab on terminal No. 1 (ORN) (A) in the 4P connector, then remove the terminal and insulate it from body ground.
    Fig 2: Identifying 4P Connector Terminal
    G08094381Courtesy of AMERICAN HONDA MOTOR CO., INC.
  5. Reconnect the 4P connector to the power transistor.
  6. Make sure the ORN wire is completely isolated, then supply 12 V to the No. 1 cavity with a jumper wire.
  7. Turn the ignition switch to ON (II), and check that the blower motor runs.
    • If the blower motor does not run, replace the power transistor.
      NOTE: A faulty blower motor can cause the power transistor to fail. If the power transistor is replaced, also check the blower motor for binding, and replace it if necessary.
    • If the blower motor runs, the power transistor is OK.
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