Re: 08 TSX: A/C or Heat no longer blowing through vents. Culprit options?
Disconnect the 4P connector from the power transistor.
Measure the resistance between the No. 3 and No. 4 terminals of the power transistor. It should be about 1.4-1.5 kW.
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.
Carefully release the lock tab on the No. 1 terminal (BLU/YEL*1, LT GRN*2) (A) in the 4P connector, then remove the terminal and insulate it from body ground.
Reconnect the 4P connector to the power transistor.
Supply 12 V to the No. 1 cavity with a jumper wire.
Turn the ignition switch 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.