My motorcycle has two 12V add-on auxiliary lights on each side of the headlight. They require the engine running and a single switch that turns on both. My 12V horn button controls a relay that provides direct 12V battery power to an add-on horn. I want to install whatever is needed between the auxiliary light switch and the lights so that when the the horn button is pressed, the auxiliary lights alternate flash. When the horn button is not pressed, the auxiliary lights are just on normally, unless their control switch is OFF. Can anyone advise what I need?

 

when the the horn button is pressed, the auxiliary lights alternate flash.

By "alternate" you you mean alternately between the two (one off and one on), or they flash together?

One way to do it alternately would be with a timer module (example) to provide the alternate action, along with an automotive relay to switch in and out, as controlled by the horn button.

 

By "alternate" you you mean alternately between the two (one off and one on), or they flash together?

One way to do it alternately would be with a timer module (example) to provide the alternate action, along with an automotive relay to switch in and out, as controlled by the horn button.

Thanks. I've since learned that what I want are known as "wig-wag" and are meant for emergency response vehicles. Definitely illegal in my state for private vehicles if blue, red, amber. The law doesn't say anything about white lights. Mine are white and by state law, are called "auxiliary headlights". The only restriction is that they can't be modified to appear as blue. I will investigate the wig-wag kits and may give it a go this winter.