I currently have one of my dipped headlights out, I have checked the fuse, swapped the relays around, checked the power going to the connector and checked and cleaned the earth all seems fine.
I have even bitten the bullet and got a new bulb

 

If the power and ground is good, I would assume the ballast is faulty.

 

Just had the same problem myself, you can swap the ballasts over but it is a pain. I ended up getting one from HIDs direct on eBay, It sort of fitted after a bit of work to get it water tight at a fraction of the Honda price.