USB charge-only to Proto module

Hi,

I am tyring to use a proto module to connect a USB powered humidifier to the arduino module. I have cut off the USB part to expose the wires, and I have one of the wires connected to ground and the other one to the volt power line on the Output side. The humidifier is working, but it is completely ignoring my code, it won’t turn on and off, the power is just passing through. I have no access to any other wires, the humidifier needs to stay sealed, and only those two wires come out of the cable. Can someone help me fix it?