Power Transistor HVAC: Testing and Inspection

Blower Power Transistor Test

1. Remove the passenger's dashboard undercover 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 kOhms.

- 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.





4. Reconnect the 4P connector to the power transistor.

5. Disconnect climate control unit connectors A (28P) and B (12P).

6. Connect climate control unit connector A (28P) terminal No. 9 and climate control unit connector B (12P) terminal No. 5 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 Blower Unit Component Replacement if necessary.
- If the blower motor runs, the power transistor is OK.