Is it possible to have corrosion in the electrical box just under the hood due to weather conditions alone? I had to replace the box in my 2006 impala and they are telling me that it is likely a result of winter weather conditions in our area.
Does your state use salt on the roads during the winter? If it does or you traveled on salted roads in other states during the winter then the corrosion is very possible.
Most of the electrical junction boxes I’ve seen lately have been plastic.
If, however, your Impala has a metal electrical box it could easily be corroded from winter driving.