I have a couple of suggestions:
First: Hand hold a temporary touch plate under the bit well above the table and let the bit touch that until you get it figured out. You'll save the damage to your machine and bits in the mean time.

Not sure what control software you run. In mach 3 there is a LED to indicate when the connection is made on touch. Same for other switches you have like limit switches. It is not dependant on code it's an electrical circuit indicator. It works any time. If the LED changes state when you touch the plate to the tool then something in the programming is not acting on it properly i.e. the double touch code. If the LED is stuck on (or off) then something is wrong with your wiring.
Of course this assumes you have the correct port input selected for the contacts. I assume you do since you had it working previously.


Sage