I got my first GC in similar wiring disaster....I got a wiring diagram and tore everything out. It about 5 problems before and zero after. It really is the best way to go after so much cannibalism
By the way old 1983 CC cart I worked on today had 1 bad micro and 2 bad solenoids. It wasn't too bad to work on. Solenoids are kinda hard to get to so I just took the whole rack out with the micro switch accelerator box attached. Only two wires connect the micros to the cart and two cables connect the solenoid rack to the cart. 2 bolts hold the rack in. I had all 5 solenoids & the owner said change em all. It was nice to have it out to do it.
Owner complained of the cart being 'slow in reverse'. Cart had the 1/2 speed (18 volts) reverse. So I took the short red reverse power cable from the F/R switch and disconnected it from battery #3 and simply looped it back to the bottom of of the F/R switch at the other red power cable terminal. Like a big loop. Result is 36v F & R. Cart worked great first try!
One more cart back to work on the ranch!