Good link Scott - the circuit they show is a bit different as we have separate bulbs on separate circuits in 2 locations. I wanted the side markers to turn off when the blinkers were on at nite but then on during the day when the parking lights are off. I believe it would take 2 relays to do this and adding a bulb was a much cheaper way to perform a similar effect and it is working well. Anyone who tries with the relays, please post your efforts.