You may want to disassemble the switch and clean it out. To make sure that the switch is being seen, you can open the Maintenace, Input screen (F6, F3) and have someone push down on the switch while you see if a check mark is displayed on the screen in any of the boxes. If you don't see a check mark appear when pressing the switch you may have a bad connection or grounding problem. If you continue to have trouble, contact us and we'll go from there.