There was a time that I was like that.
Then----- shortly after I started wrenching for the Montana DOT there was an old wore out Alice Chalmers Loader that the engine was getting tired in,it also had multiple electrical problems,Always something or other shorting out,I was assigned that project.
Out came the engine,then the center pivots and electrical harness,completely stripped out,tagged each and every connector then stretched that harness out on several old plywood signs,nailing down each comnnector and splaying that harness out,cut off the electrical tape,banding a piece of tape around the harness at the intersections then duplicating that harness,less the connectors,got it complete then cut the pigtaqils off the old harness and soldered them onto the new harness,except for the ones that were availeable.
Completely rebuilt that old Alice,front to back,top to bottom,and all the hydraulics in between.
I got that old critter back together and every electrical item in it worked perfectly,the first time.
That ended My fear of electricals,what a good lesson.I learned to always start with the grounds,unless it was something real obvious.
Throughout My 31 years with them there were a lot of wiring issues but I never had another project like that one again,although,I was restoring a 1957 Triumph Thunderbird motorcycle and rebuilt the harness for that,it was easy compared to that old Alice.