These wire harnesses are exact repros of the originals, you do not need to modify anything:it is simple, man: disconnect the old one carefully and connect the new one the same way , not much to it! Don't be afraid of doing it yourself, remember you are not modifying anything, just disconnecting and reconnecting. If you run into any trouble, don't hesitate to call me 7 days a week at 918-753-2486, I will be glad to walk you through it. Don't forget that these wire harnesses are about 40 years old, heat and age have taken their toll. Replacing your harness will avoid many electrical failures, which, as we all know, can be very frustrating. I know that from experience with my own cars. I learned the hard way, trying to be cheap by repairing the old harness again, just to run into another problem! It's not worth it , I assure you. Save the headache, and just DO IT, DO IT !!