Truck will not crank. Previous owner installed crappy kill switch that initially started the problem.I by pass it and truck was running fine. Till the a ground cable came loose on the battery. There's some power because I get a flashing from hazard and a clicking from pcm. Is the ignition switch a possibility? The battery is new(tested/fully charged). All terminals have been check and secure as well. Thanks!!

Take out completly the kill switch wiring. make sure that all wires are secure, especially around starter.
check switch on ignition by bypassing. take a wire from coil to battery (pos to pos) , cross the two terminals on stater/solenoid to start. if starts then could be bad ignition switch or bad solenoid.
plus make sure all ground wires are secure. should get you going.

It would be the ignition or those ignition wires because of the kill switch being poorly installed, id try tracing wires first and replace anything thats been cut/spliced into. if not change the ignition