Most likely, the DRL lower brightness is driven by a PWM (pulse width modulation) circuit that is chattering the relays. This is a BAD thing. You'll need to completely disable the DRL function or you WILL damage your relays and ballasts. IIRC, the DRL control module handles all the headlamp functions, so this will be no easy task. You may have to go all the way back to the headlamp switch and tap the "headlamps on" trigger directly to enable your relays under the hood, and completely ignore the stock headlamp connectors.

Until you get this resolved, I HIGHLY recommend that you remove your HID and relay kit for the time being.