I had the same issues with a wiper motor on my 2000 Chrysler(Dodge) Intrepid. The wipers worked, shall we say, intermitantly, especially in cold weather.
The dealership said there was nothing wrong with the motor cuz when they tested it, it worked fine.
Had to go through Chrysler Canad's head office to get it replaced.

SO, if this dealership is giving you a hard time. deal directly with Honda's American head office customer service dept.