I am all for doing anything that will enhance other people seeing me. I had a headlight modulator on my other bikes and wanted one on my Concours 14 as well. I bought a kit from Kisan. Installation is fairly simple.
The kit consists of two electrical connectors that go between the headlight plug and the bulb. One is marked master and one is marked slave. It doesn't matter which one goes on which headlight. Each electrical connector has a place to attach another connector for the light sensor. The light sensor connector with multiple wires must attach to the master and the single wire connector attaches to the slave unit. The light sensor must be installed so that you can use your high beams at night without them flashing.
The upper black plastic trim pieces on each side must be removed. To remove them, you remove the three screws and one plastic fastener under the windshield. The windshield must be removed to access this fastener. Fortunately, removing the windshield is easily done by first removing the black trim pieces and them removing the single fastener on each side that is hidden by the trim piece.
Once you have the plastic pieces removed, you can access the headlight connectors. Simply remove the factory plugs, install the modulator plug onto the factory plug and then plug the modulator plug to the headlight bulb. Run the wires for the light sensor to one side or the other and make sure they are free from any obstructions.
The light sensor must be mounted so that it sees light at all times. I drilled a hole in my left side top plastic trim piece and mounted the sensor there.
Re-install the black plastic pieces and you are finished.
To use the modulator, you simply put your headlights on high beam. The lights will flash constantly. If you want to turn the flashers off during the day, put your headlights on low beam. They are very noticeable. On my other bike, I was stopped at a stop light when the car in the next lane asked me if I knew my headlights were flashing. I told him yes and he asked why. My reply was so that someone like him would see them and hopefully not pull out in front of me.
At the same time I was doing this, I also installed a mount for my GPS. I bought it on EBay.