xj53

i have a 2000 jeep cherokee sport that i am looking to build.
i turn 16 in about two weeks and will be getting my license then
its got some rust and 150k on the odometer. the rust isnt that bad and as long as i keep my engine maintained im sure it will run well past 200k
it currently has the check engine light on so i took it in to get the code read and its just an after cat oxygen sensor so easy fix there, did the same thing on my moms old f350 centurion.
but i do need some help with my rear hatch, when i first got it the hatch wouldnt open because the latch on the actual hatch was missing both bolts that hold it in place so i replaced those and now it opens and closes no problem. However, it only unlocks and locks about half the time. i am worried that sometimes when i unlock my car it will come unlocked then i lock it, it will not lock and my rear hatch will still be unlocked while the rest of my car is locked.
ive searched on this forum for a fix but havent found a thread on it. any help would be great because im totally lost.

future plans include either a 2 inch BB with some fender flares or a 3 inch lift. i am looking to run 31's. currently it is on some 235's. i also need some recovery points up front either by junkyard hooks off an up country cherokee or an aftermarket bumper.
my only income is umpiring little league baseball so i cant go much more extreme.