On my 99 Bonneville, the DRL can be disabled by pulling a two pronged connector out of a cermaic resistor in the driver's side fender well next to the horn.
To kill the "Automatic Headlights" on my 99 Bonneville, you need to pull the top of the dash out and disconnect the light sensor. Replace the sensor with a 2.2kΩ resistor. The resistor fools the lighting computer into thinking that it's always sunny.
Just remember, keep the modifications to your electrical system simple. You may end up having to put them back some day.
