Had this also happen to me on my 03 Accord,
Under the passenger side dash you will find the blower motor and also part of the heating/ac unit. On the firewall side under the dash you will see a transistor with a plug and two screws attaching it. When you take it out it will look like a heat sink, that is the transistor that controls the fan speed. You can also test the blower motor before buying the transistor. To test the blower motor, disconnect the plug and connect positive and negative to the contact. Careful not to cause any sparks.
I was lucky to pick one up at the junk yard, but if not then here the part number from Honda
79330-SDA-A01 TRANSISTOR, POWER No Color
About 45-65 dollars.
Hope this helps
Tuesday, December 1st, 2020 AT 12:58 PM
(Merged)