On some newer cars that use halogen headlights as a DRL and low or high beam on the same bulb. Is there a module or a circuit that senses the change from drl pwm to full voltage output available? What I am thinking that if a resistor and cap across the output going to the headlight the dc voltage change should be significant to use a battery voltage detector ie 741 op amp and drive a relay to provide two outputs, output 1 to drl led and output 2 12v to drive headlight high or low beam. Most people are using relays and getting 12 volts from the battery. Getting all the power from the headlight lead this way would retain the factory cars response to when the drl and headlight is on or off when driving the leds.