check to make sure it's not the wiring too. I'd go into the switch test, maybe throw your switch wire on the NC terminal, and just wiggle the wires to see if there's a flash at all. and if you wanna check for broken grounds, if the grounds are in like a daisy chain, go to the first one that's not a splice-in to a switch you got on NC and wiggle there. then deduce along the line if any of the spliced ones may be broken.
I re-did a 6 speed shifter on a Ridge Racer that had the same problem, I just soldered the wires direct onto all new switches, and ran my own grounds and just connected the ground wire off the harness to the first switch.
and if this makes no sense, I'm sorry, I just woke up lol