A few comments.
In a quick search it seems the 1720 was made starting in the late 80’s until 2000.
•Tech changed a lit over those years. I do not know if the 1720 stated with the same late 80’s tech or not.
•Late 80’s wiring would be fairly straight forward and simple to repair/replace, but very very time consuming.
•If the mice liked the older wiring insulation, you ain’t seen nothing for newer wiring which they truly love to chew.
•Working under the dash is a pain under the best situations. Make sure you have plenty of time complete the project when you start in on it. Just the getting access is a pain.
•Try to get a manual that indicates the wiring diagram as well as wire colors and follow wire colors when replacing. This will allow the wiring diagram to be useful in the future.