That vehicle doesn't use a conventional resistor array for blower speeds, it uses a pulsed wave control that turns a transistor mounted on the blower motor on and off in pulses to adjust the blower speed. They can fail open or shorted normally and they work by turning the ground connection on and off. So shorted would give you full speed regardless of the settings and open would mean no blower. Testing is somewhat easy as the transistor only acts like a heavy-duty switch, so you remove the lower sound deadener pad under the right-side dash. Then access the blower motor and the controller. With it turned on unplug the wiring connection, now use a test light connected to ground to gently probe the red wire, turn the blower to high speed and back a few times, the light should go from full brightness to dimmer as the blower speed goes down, it should go out if you switch the HVAC off. If that works it is the transistor, Honda part 79330SDGW51. Replacement is simple, remove the two screws, pull the module, install the new one and reconnect the connector. Then reinstall the sound deadener panel.
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May 4, 2022 at 10:18 AM
