I spent a couple of hours yesterday coming up with a circuit to get the fog lights to go on as DRL instead of the using the lo-beam lights. From my experience with my HID conversion, I believe the lo-beam lights runs at reduce power when in DRL mode. This is accomplished by sending a Pulse Width Modulated (PWM) signal to the lo-beam lights. The ratio between the on and off time of the PWM signal determines the power (or brightness) of the lo-beam lights.
Based on this assumption I when ahead and designed a circuit, here is what I have come up with. I have tested it on a test bench and it works like this:
DRL off ----> Fog lights off, lo-beams off
DRL on ----> Fog lights on, lo-beams off
Lo-beams on ----> Fog lights off
With the lo-beams on, the circuit still allows you to turn the fog lights on. You can still manually switch the lo-beams and fog lights on and off using the factory switch next to the steering wheel.
As I have mentioned before the hardest part is to locate a source for the proper H11 and H7 connectors to build a wiring harness so one does not have to cut in to the original factory harness to do this mod. Here is the schematic, anyone with suggestions are welcome.
PS:Is it legal to use the log lights as DRL?