I am interested in doing this mod. I'm not an electrician, but if I have a diagram I usually do just fine. I installed the passing lights yesterday, and I ended up using the instructions that came with them to install them. I bought a relay, and distribution block, but didn't use them. After seeing this, I might hook up the delay relay, and distribution block. I am posting a picture below. What if I use this set up, only replace the regular relay with the timed relay? I can still wire in the toggle switch for the passing lights, and wire the positive, and negative headlight wires into the distribution block. Any thoughts? Will that work?
Edit: I used the red with yellow stripe lead for my power soure for the passing lights. I would use that also instead of the running light for my switched power source for my set up.
Here is the picture.
http://www.canyonchasers.net/shop/generic/_img/relay/relay-diagram-final.jpg