Double check your wiring for proper crimps and connections and also possible opens (both in the signal wire and your ground circuit). Verify the signal wire is connected to the NO terminal of the microswitch and also verify you have continuity across the switch's ground pin and NO pin when the switch is made. Also, I've come across quick disconnect terminals that need to be pinched a little to make a proper connection with the switch spade, make sure yours isn't loose.