Q: Installed a new ignition harness after the old one required repeated key giggling to start the car, now won't start

First I installed a PCM ignition relay board successfully and then found out it was the ignition switch harness that needed replacement. I installed an Autozone harness and now the car won't start. It turns over fine and the dash lights work put won't start. I suspect something to do with the immobilizer because the door alarm no longer activates or sounds off. Not sure why when I did not replace the actual mechanical key switch tumbler and I never removed the immobilizer and I'm using the original key. I re-installed the old harness that did work with a giggle or two first and now it no longer works...the car still won't start. My issue is the car has a aftermarket stereo and I'm unable to locate the security code/reprogram number that was in the glove box. Please help. Mel

My car has 130000 miles.
My car has a manual transmission.