Steve, any particular reason you didn't also do the highbeam?
As Toxz Qwaste said, cycling a HID light on and off is not recommended. It drastically shortens the life of the bulb. (HIDs also don't hit full brightness for a few seconds after turning them on.)
I have an H4 HID conversion in my C10. When the light first goes on, it flashes brightly and then goes
really dim before gradually coming up to full brightness. It uses a solenoid to move the bulb from a high to low position, and really throws a lot of light down the road. I'd rather go with Murph's setup, but it isn't in the budget yet.