Wiring problem

Hello everyone,

I have installed a nos system on my car, i am running a motec m600 on the car. I have connected both the fuel and nos solenoids to a switch and the other part of the wiring to an aux output, everything worked fine but the problem is when i checked the pin of the aux output, it had some current running through when the switch is turned on ( even when it is a ground ) so does this effects the ECU, can it damage the ECU or is it normal?

Thanks

Due to the way that the pins are driven, it is possible for there to be a small voltage floating on the pins.