EZSnow on the Snowplow Contractors (registration required) has posted the wiring diagrams for momentary blinking of your running lights. I have done this mod and it works great. If you hit the switch your running lights (including trailer lights) will blink on if they are off or off if they are on. The headlights are not affected. The dash lights will flash as well which can be mildly distracting until you are used to it. I have posted links to these diagrams before but since the archive is not very functional, here it is again.