Woo Hoo! Finally figured it out. Look Ma, NO DRL's!Halos stay on.....no way to turn them off.
After a lot of trial and error, it turns out the white halo DRL's are controlled by Pin 14 (Front Sidemarkers) on the Headlight Lamp Assembly connectors. Running on only 1 volt this circuit turns on side markers at night (headlights on) or when the parking lamps are on. But in daytime (ie: headlights off and parking lights off), the same circuit supplies 12 volts for the bright DRL's halo's.
By using a mini 15 amp step down buck voltage regulator (inside a small plastic project box) for each side and directing the circuit thru it, reducing the voltage below 5 volts shuts them down completely, yet still supplies enough voltage (1 volt) for the side markers to still work. Luckily, the BCM does not check line sense voltage on the side marker circuit. Thus, everything else on the lighting system continues to operate normally.