no fire to plugs, changed cam, crank sensor, happened aafter i replaced the ignition swicth

I'd start with the new switch and make sure it is the correct replacement part. Then are all the wires correctly connected? Does the power reach the areas it is intended to go to? If this happened "after" the switch was changed out, are you just throwing in replacement parts in hopes of finding a bad part? Who or what told you the sensors were bad? You change one part and something does not work, then go back to the new part and exchange it. Or were you guessing at what the problem was in the first place? What was your initial problem. Let's start from there.