Mr McBride's harness came to me with numbers at the terminals, and he supplied instructions and some tricks to getting it back in the car. I left my old one in place until I was ready to install the new one. Remember that they did this on an assembly line, so think how they might have done it then. It had to be somewhat simple and fast to install. I got the main harness through the firewall then wired the motor area first, then moved under the dash. It was easier than I ever imagined, but you do have to be careful.