Whats the single black wire that comes off the steering column?
 

Theres a single black wire that comes off the new steering column I put in my car. Its cut and not hooked up to anything. What is this wire, where is it supposed to go, and could it being disconnected have something to do with my car suddenly refusing to crank?

good chance the cable is for the transmission gear selector interlock system. when functioning properly, the system prevents the vehicle operator from removing the keys from the ignition unless the gear selector is in "park".

Probably airbags if you got em, or horn. Dont know what else it could be.