Funky Power ISSUE NEED HELP!!!!!

[ChicagoS14]

Okay, so im stuck on an issue that is probably a small problem but very annoying. So i recently put back my car together as I just completed a KA-T project using the IAP kit. Car turned on fine and was running. As soon as I took it for a drive I noticed a power failure. We ran a test and the alternator wasnt putting out enough juice to charge the battery. We tested the battery and its good. We installed a new alternator and the same issue remains. The alternator is hooked up correctly all electrical things in the car work but off the battery, the car dies when the battery gets disconnected while its running, no fuses are blown and I have no clue what to do???? Only Issue i know of that i found out recently is that one of the sensors running to the tranny might be disconnected/severed, since my reverse lights stayed on permanently, so I took out the bulbs to prevent the battery from draining. I need help !!!! Thanks...