Weird!
So you replaced the Actuator Pin assembly but kept the original Ignition Switch?
You may just have a loose connection in to the ignition switch area.
There are two problems that have been reported when replacing the Actuator Pin Assembly though I do not see how that could relate to your problem.
The pin assembly is hollow inside and has thin sliver that protrudes when the key is inserted....this presses on a small separate switch within the ignition switch and produces that "Ping" when you open the door when the key is inserted. Some owners have that sliver too long so it gives a constant Ping even with key removed and others the sliver was too short so key in ignition switch was never activated.
Other problems with a new pin assembly is its radial relationship to the ignition switch ie. too far clockwise or counter-clockwise. My Export 2002 CRD Manual picked up a problem when still fairly new in that when I turn the ignition ON I am supposed to depress the clutch pedal so the clutch interlock switch make and then I can turn the ignition key that final step to start the engine.
In my case as soon as I depressed the clutch the engine would turn over without me turning the ignition that final amount so I elongated the mounting hole in the ignition switch so as to retard the switch position a fraction.
Other owners had the ignition switch not making the final movement so the engine would not turn over so they had to advance the switch position slightly.
Have a good look at the ignition switch/actuator pin area for any loose wires or fitting issues.
You can leave the ignition switch off the end of the pin assembly, place key in its slot and turn it all the way so as to unlock steering lock and enable SKIS anti-theft. Then turn the ignition switch with a small flat screwdriver to start the engine and take a short drive like this to see if you problem returns.
Moving the steering column up or down while working in that area may have shorted or moved some wire in that area. Check the connections to the SKIM module at the top of the steering column which does the reading of the inserted chipped key.
Read up on how the TPMS system works by downloading the Jeep KJ Service Manual for your year KJ here if you have not already done so.
Manuals:
http://www.colorado4wheel.com/manuals/Jeep/KJ