I changed out a complete dash harness on a 70 Coronet R/T. I found a nice uncut one at a salvage yard. I took a tablet to draw a diagram and pulled the instrument cluster loose so I could see behind it. You may have to unplug the speedometer. I drew a little diagram on the tablet of what colors plugged in where and shapes of the plug ends. I took out the entire harness without any damage. When I put it in my car, I again took a tablet and drew a little pic of my cluster and what plugged in where. It was very easy putting the replacement harness back in my car. I planned on doing the same thing with the dash harness on my 69 Dart GTS. I have a couple of complete harnesses. My Dart has A/C and that would be the only thing to keep in mind. Non A/C and A/C harnesses are slightly different.