I have a ranco on one of my racks. I have little to no light on the power strip either and I know its on. It still runs fine and gives me heat.
Is this a new thermostat? Have you given the flexwatt time to warm up? Maybe crack the thermostat open to check the wire connections. I wired the power strip into the thermostat unit myself. And Reptile Basics does the same method. If yours looks like theirs, then you can't directly plug the strip into the wall as there is no prong plugs. Nor can you plug the flexwatt directly to the thermostat as it has no outlet unless you have a stock Ranco that isn't modified.
Maybe try plugging a light or something else into the strip to see if it that will turn on.
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