On prior coach (Forest River C) the icemaker valve was located outside in a panel that housed the refrigerator mechanicals (water and electric hookups). the panel was a plastic grille on the side of the coach immediately behind the refrigerator. The valve was a push pull type valve with a round knob. I would imagine yours is something similar.
US Army (Ret)
2020 Entegra Accolade 37TS
2019 Jeep Grand Cherokee Trailhawk (Toad)
FMCA - F432054