The FREEDOM+ removable power module has been designed to automatically switch off when water gets into the connector, the water will not cause the product to fail or short out.
Water may get in if it’s not seated correctly or screwed down, or possibly the deck housing O-ring connector has worn out. You'll see a build-up of material around the pins or on the connector, often green in color as shown below, this is salt reacting with the pin material.
This is fairly easy to clean with bicarb soda, a very cheap non corrosive house hold cleaning agent, the bicarb soda can be used to clean the electrodes. Create a paste one third water 2 thirds bicarb soda and using an old tooth brush scrubbing the pins and / or connectors, usually you will need to clean both. Once clean let dry and your good to go.
Alternatively, buying a tube of Electroguard grease helps prevent the corrosion and moisture to the pins.