It was a pleasure talking to you on the phone. I am thrilled that we solved this problem and at very little time or cost to fix. It makes me happy to know i made someones day with my advice.
Here is a little recap of our phone call for you to refer to as well as others that might come across this post that can help them with same type of problem.
Your problem as discussed is, your son -in-law had just bought a bike, and it has lower add on fog/head lights, that keep blowing the 10 amp fuse. It was like this when you bought the bike. So, after us talking, besides the 10 amp is not sufficient for 3 additional headlight and the main head light is the reason it is blowing fuse. To confirm this, is after talking to you, the person who added these additional 3 headlight/driving lights, also taped them into the main head light. Which is way to much for a 10amp fuse. Besides that , I also added for safety wise it is for sure a NO NO. I said , because you could be driving down the road at night, and because all are tapped in together, then when fuse blows, now you have no lights. Yes, I said you can find another circuit to tie into, but i recommended the best solution for easiness, safety and effectiveness, is to run the hot lead off your toggle switch (that operates your 3 additional lights) Run it direct to your battery positive terminal, with a inline fuse. Make sure you have the proper gauge wire for the amps being pulled by the 3 lights, and run the proper gauge wire, with of course the proper inline fuse, Problem is solved. You thought that was best idea and cost and for overall safety. I am glad I can help, and let me know if you have any other questions. Mike from Fixya