Power Transistor Test

WARNING: This page is about a different car, the 2008 Acura TL and 2007 Acura TL. However, it is still accessible from the selected car via links, so may be relevant.

Disconnect the 4P connector from the power transistor.
Measure the resistance between the No. 1 and No. 2 terminals of the power transistor. It should be about 1.5 kΩ.
- If the resistance is within the specifications, go to step 3.
- 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 No. 1 And No. 2 Terminals Of Power Transistor
  Courtesy of AMERICAN HONDA MOTOR CO., INC.
Carefully release the lock tab on the No. 4 terminal (BLU) (A) in the 4P connector, then remove the terminal and insulate it from body ground.

Fig 2: Removing Terminal And Insulate From Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Reconnect the 4P connector to the power transistor.
Make sure the BLU wire is completely isolated, then supply 12 volts to the No. 4 cavity with a jumper wire.
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.