Just a quick note to say thanks for everyone for the help and especially to Syfi for all the detail and the pictures. With all of your help I expect this project to be somewhat easy now that I don't have to reinvent the wheel.

Just for the heck of it point your browsers to Hot Reduce Car Light LED DRL Relay Harness Automatic on Off Dimmer US Seller New | eBay and see what you can make of this thingy on ebay. If it works like they say it would be pretty neat but I have my doubts about it consistently working. Are they just assuming that there will be more voltage to the battery when the car is running than when it is not and the extra voltage would trigger it? Anyone got any ideas?