I had the same problem on my 1995 Honda Odyssey. The buzzing sound is
coming from the actuator. There's a little rack/pinion drive inside the
actuator, with a rubber stop at each end of the rack gear. When that
rubber bumper wears out or gets displaced, the rack gear travels past
its limit, and the pinion gear (connected to the little DC motor inside
the actuator) spins off the end of the rack. The buzzing sound is the
sound of the pinion gear grinding away off the end of the rack (and
doing further damage!).

There are two possible solutions:
(1) Replace the actuator outright. Removing the actuator is a pain and
involves removing the door panel, handles, latches, etc. You can get
the actuator off without removing the other stuff (three screws), but
good luck getting it back in. (To access the difficult bolt, on the
Odyssey there is a hole in the door itself that's covered by a piece of
black adhesive material, almost like a piece of electrician's tape.
Remove the tape, and you can reach the bolt directly with a socket
extension. I can't speak for the Accord, but I expect it may be
similar.)

(2) If you're a real do-it-yourselfer (read "cheapskate"--like me! :-)
), you can remove the actuator, disassemble it, and use some RTV
silicone to mold replacements for the rubber rack stops. This is a very
workable solution for an investment of about $5 for a tube of silicone.
(Make sure it's well cured before you try energizing the actuator!). If
you're going to remove and replace the actuator yourself, you may as
well try this solution.

I'd be interested in receiving comments from anyone else who tries the
RTV silicone replacement solution. Let me know how it works.

Best wishes!
Juan