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Power Transistor HVAC: Testing and Inspection

Power Transistor Test

1. Remove the passenger's dashboard under cover.
2. Disconnect the 5P connector from the power transistor.




3. Measure the resistance between the No. 1 and No. 4 terminals of the power transistor. It should be about 1.5 kOhms.
- If the resistance is within the specifications, go to step 3.
- If the resistance is not within the specifications, replace the power transistor.




4. Carefully release the lock tab on the No. 3 terminal (RED/BLK) (A) in the 5P connector, then remove the terminal and insulate it from body ground.
5. Reconnect the 5P connector to the power transistor.
6. Make sure the RED/BLK wire is completely isolated, then supply 12 volts to the No. 3 cavity with a jumper wire.
7. Turn the ignition switch ON (II), and check that the blower motor runs.
- If the blower motor does not run, replace the power transistor.
- If the blower motor runs, the power transistor is OK.