How Do I Install Or Repair The Trunk Occupant Presence Sensor?

2002 Chevrolet Impala LS 3.8L v6 My Service Vehicle Soon light has been on for some time now and the code I repeatedly get is B3896 which is related to the Rear Compartment Occupant Sensor. In the trunk connected to the radio receiver was ACDelco PT316 connector. A wire harness but the wires didn't go anywhere they looped back into the connector. 3 wires red w/ black stripe on one end orange with black stripe on the other end and grey in the middle. The two stripe wires were crimped together at the end then a diode was crimped to the end of the grey wire and the other end of the diode soldered to the crimped red and orange wire. The wires on this we corroded and broke. Took me days to even figure out this was related to the occupant sensor in the trunk which I've still never found or seen. Anyways I managed to purchased things and recreate whatever this 9 pin female connect with 3 wires in it was. Plugged it into the side of the amp or whatever it is in trunk lid in the middle of the two speakers and all the sudden the truck light came on. I was so thrilled and that must mean i fixed it. But no service vehicle light still on. The code same B3896. I know the bcm is working because it does everything else its suppose to. I can't feel or tell any difference in driving other than once and awhile the red battery light comes on while I'm driving and then security light and then they go off. I used the scan tool to clear the code and service vehicle soon turned off for maybe 10 seconds then came back on. When i use to scan tool to go directly to the TrapAlert System Settings the scan tool says loss communication and resets every single time. No i can't pull the fude because the same fuse is for the cluster and other things so the wont turn on without it. Ive contacted gmc and chevy and were told they don't keep information over 10 years. Also the ACDelco PT316 is a discontinued part of course. Still I'm able to find a few online but it has many wire leads not 3 like on the one I'm trying to replace so idk where or how to install it. Ugh also sadly I've now had vehicle service twice paid around $1200 total now for them to diagnose and have no idea what a "rear compartment occupant sensor" even is and the other to claim it was fixed n that the service vehicle soon light was for something else so i went and got an oil chage as he suggested but it's still on and I'm still only getting the one code. I've unwrapped and looked at all wires see nothing wrong rewrap and just keep on going in circles. Owners manual suggests there is a switch on sensor to disable i disagree I've taken the seats out and back ledge and wripped trunk apart I do not see anything about a sensor) i replaced deck lid switch and acupator and also the wires from the radio harness loop thing to courtesy lamp. I just keep wasting hours online searching for an answer and trying to guess. I hate the light on my dash makes me feel like my car is trash and its really not. I wanna fix it but I've now spent more then it's worth and have literally gotten no where. Ahhhhh its so frustrating