Power Transistor HVAC: Testing and Inspection

Power Transistor Test

1. Disconnect the 5P connector from the power transistor.




2. Measure the resistance between the No. 1 and No. 4 terminals of the power transistor. It should be about 1.4 - 1.5 kOhm.

- If the resistance is within the specifications, go to step 3.
- If the resistance is not within the specifications, replace the power transistor.




3. Carefully release the lock tab on the No. 3 terminal (ORN/BLK) (A) in the 5P connector, then remove the terminal and insulate it from body ground.
4. Reconnect the 5P connector to the power transistor.
5. Supply 12 volts to the No. 3 cavity with a jumper wire.
6. 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, replace the climate control unit.