Power Transistor HVAC: Testing and Inspection
Power Transistor Test1. Disconnect the 4P connector from the power transistor.
2. Measure the resistance between the No. 1 and No. 2 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.
3. Carefully release the lock tab on the No. 4 terminal (BLU/YEL) (A) in the 4P connector, then remove the terminal and insulate it from body ground.
4. Reconnect the 4P connector to the power transistor.
5. Make sure the BLU/YEL wire is completely isolated, then supply 12 volts to the No. 4 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, the power transistor is OK.