well when I do my light kit, the HEad lights and taillights will be on their own batteries... 3v for each one... and the brake lights will be a parrallel wireing with resistor on the PCB motor terminals
so only on in reverse...
so just tapping it will flash the brake lights...
the mercury switch will only work if you dont shake the car... and it shakes and bounces/vibrates a lot... so it will be sorta strobish.