I'm doing a project on my car where I have a clutch position sensor that moves when the clutch throw-out arm moves. Due to some new improvements on the car I need to have the ability to bypass the sensor on occasion, yet simulate the operation has occurred to the transmission control unit. The sensor sweep is 4.75 volts to a little less than 1 volt. The modification will prevent the sensor from actually moving on certain occasions. I want to intercept the sweep signal using a relay, then reproduce it electrically to send back to the TCU. How can I reproduce a drop from 4.5 volts to about 1 volt electrically? I friend mentioned using a 555 timer, but I have no idea what the values would be to achieve these results.