Try wiggling the switch, applying light pressure on all sides of it, flick it on and off. I still have to address the poor wiring job from Heartland behind my control panel. Too many wires in too tight of a space (depth wise), causing pressure on the connectors, connections, and switches. Sometimes an item I switch on does the same thing, or it flickers. Pressing on the whole panel, or the switch corrects the problem. For me I will have to inspect each crimp connector for proper crimp, and possibly switch out many of them with 90 degree crimp connectors.