Here's my guess.
On my gf's pontiac grand am, she lost low speeds speeds 3 and 4. It turned out to be the
blower motor resistor that was bolted to the firewall under/behind the glovebox. Apparenlty the stock resistors were not coated in any waterproof coating. So whenever humidity gathered on the metal firewall, and dripped down, it would soak the resistor. Found the replacement (which was waterproofed) at autozone for $20.
Again, I'm thinking it's the same problem, but I honestly don't know where the resistor is located on an '00 Accord. You could try getting a service manual from either Autozone or downloading one
here. Or maybe someone can chime in and tell you where it is. I basically just bought the replacement, and then looked around under the dash/glovebox, until I found an identical looking part.