Hooking up light buzzer

[Ivan141]

I put one in my moms car once, it came with instructions. You either have to wire it into the door-switch, which is a bit fiddly, or you can wire it to go off when the ignition is off and the lights are off. To do this you can usually just poke some wires in between 2 fuses in the fusebox. (ignition and lighting fuses). It's basically just a buzzer with a diode in series. When the ignition is on and the lights are off it gets 12V from the ignition and 0V from the lighting fuse...the diode blocks the current in this direction...when both fuses are powered (ignition & lights on) there is no difference in voltage and no current will flow. When the lights are on and the ignition is off current will start flowing in the right direction and voila...it will buzz. All you have to figure out is which way the wires should go.