Power gear Jacks alarm sounds when retracted

Thanks Doug your right, it's an Equalizer system on my 2017. I thought it was made by Power Gear? Guess I'm wrong about that. It always alarms if it sits a long period of days on my off level pad. So I wasn't sure if perhaps a jack was bleeding down, but your explanation really helps. Is that pressure switch inside the oil reservoir or on the jacks ? I figure it will need attention some day.