This disclosure describes techniques for increasing wetting current for an electromechanical switch. In one example application, an aircraft may include one or more valves used to control the temperature of aircraft interior. The valves may include one or more valve position switches to indicate certain valve positions, e.g. fully open, fully closed, fifty percent open, and so on. In some examples, the valve position switches may receive current at electromechanical contacts of the switch that is less than the wetting current. The techniques of this disclosure provide additional wetting current at the time the switch contacts close to improve reliability of the valve position switches. In some examples, an analog to digital converter circuit may be configured to provide the additional wetting current to the switch.