I had problembs with taping the signal to on the buzzer with machine tower light.However I try to connect parrallel to the light but the control board which connected to the light malfunction after 1/2 hour.The tower light is trigger by the ground signal.(Short to ground when to on the light).Pls advice any circuit which can taped the signal without any damaged to contol boards.
You can use a Power Mosfet to drive the light (I am taking for granted it is a DC Voltage the one that turns the light on), the only current a Mosfet demand is only to charge its input capacitance this way you will not damage your board. Configuration is so simple, signal goes at Mosfet Gate, set the load(light) between V+ and Mosfet Source and connect Mosfet Drain to Ground. Check Motorola's data for Mosfet spec.