Carl and I have run into trucks we bought with all that stuff you mention. Back in our Dad's day, (actually my day too) all they had was sticky cloth electrical tape. After years of heat and cold cycling, that tape is how Gorilla Glue was discovered....or was it Phil Swift's Flex Seal?
Otto, Now that you have become a sparky, as we used to call the Electrical Engineers, I agree you are ready for a new harness after this.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn