Headlight relays use the stock headlight system to only throw the relays, one for high beam and one for low beam. The relays route power to the headlights directly from the battery or a fuse panel if the rider installs one. All the contacts and connectors that are prone to fail from carrying high currents are bypassed and the beefy relay contacts rated for 30A or more carry the power instead. The relay contacts are rated to carry more power than the entire bike uses.

If you use heated gear and a duty cycle controller, the headlight relays will stop your lights from dimming when the controller kicks on. It will also make your halogen headlights slighter brighter and cause them to burn out a little sooner.

Sorry but relays won't keep the headlight from cycling with a heat controller. Turning high draw heated gear on and off every second will make the headlights modulate even with relays. I used to be in that situation. HID lights that keep a constant brightness from 9V-16V will prevent that.

That's odd, Pat. The relays definitely stopped my lights from dimming with the controller. It used to drive me nuts.

How much heated gear are you running? With Warm and Safe 90W jacket liner, gloves and HotGrips, it looked like I had a headlight modulator.

Similar load here. I think I had both the relays and heated gear connected directly to the battery rather than through a fusebox. That may account for the diff. It's been awhile, this was on my '05.

Maybe you didn't notice. I was using it for over a year before I noticed something was odd and faced a store window.

That's why I bought the headlight relays, to make the modulation go away.

I did 87,500km on my 2004 Wee Strom. I rode it to and from work every day for 8 years, and I never had any issues with the headlights or electrics. So I don't see the point of a headlight relay kit.

There have been switches go bad on a number of people.