Thanks for your reply. I received the new pressure switch and was simply able to disconnect and reconnect the wires to the new switch. Still not sure what the wire that runs into the ground actually does but it was a fairly easy fix once I cut away the black sealant. This sealant covered the wire connections. I plan to reseal the connections but, for now, just have electrical tape wrapped around them. This gage is apparantly a pressure switch for my gas heater. Again, thanks for your reply!