If it's only leaking when calling for water, it is likely the outlet from the solenoid, not the inlet side. The outlet uses a compression fitting; a compression nut that compresses a compression ring That compression ring is what actually stops the leak. If yours is leaking, maybe that compression ring unknowingly fell off. Did you see that the compression ring was on the plastic pipe and under the compression nut before you assembled the connection? This connection must be opened to blow out the icemaker line above the solenoid; technique is to NOT assemble the connection after winterization so that the guy doing the de-winterizing notices it and pays attention to this connection not leaking.
2006 Monaco Safari Cheetah 40PMT