[Nutbutt]

Don't know what kit you are using but the DRL voltage is pulse width modulated to get to a lower voltage when the drls are suppose to be on. I am driving my fog lights off this trigger an had to put a 10uf cap from the trigger to ground and a diode in line of the trigger to protect the cars computer which does the pulse width modulation. If you don't do this even using a relay may result in the same flickering and a chatter from the relay.
I'm surprised that the HID headlight relay in your system doesn't have this built in? I would call the manufacturer before playing with the circuit.