Matt, what is the condition of rest of the bike, such as exhaust and chassis and rear subframe? The reason I am asking this is because all parts on a vehicle are subjected to a salt spray test, which simulates conditions such vehicle being used in winter, being used at coastal regions etc.
If the rest of the bike is in very good condition (no significant corrosion) and is just a particular region of the wiring harness that is corroded, then you can write to Suzuki saying that they have not done enough to protect that area from corrosion.
You can prove to them that since the rest of the bike is in good condition, it has not been used in winter excessively and has not been subjected to conditions that would cause above average levels corrosion.