My first 262c was a 1980. The harness started to fall apart. The only part I kept was a small section that went into the large grey plug at the firewall inside the engine compartment. At the time I did not have the funds for a new one. And didn't know about Brickboard or Turbobricks to source parts. So off to the auto parts store I went and purchased automotive wire in all of the right colors. Carefully removed the old harness, made notes of what wire went where and made a new one. Took a few hours and the car was back on the road. This may be an option for you. Note all the wire colors were the correct colors for each location. If it was green originally that is what that connector got. I also could not find, locally, yellow wire with blue tracer. This was solved by using yellow wire and running it over a permanent blue ink marker. Problem solved. Good luck, you can do it!

Tracer wire trick will work for any color combo you need.