Depends on a few things.

1. How far back does the damage go. (You'll have to open the harness and find out where the cable is still flexible by hand. A visual inspection won't be enough)

2. Is there enough slack in the cable to reach. (After performing step 1)

There are splice cables and terminal assemblies available if it doesn't reach.

Using a design that solders to the existing cable is preferable, but crimping and using marine grade shrink tubing is second best.