Very few new cars that don't use soy based insulation. GM included. Mice and rodents have chewed on wires for as long as there have been wires. Studies indicate that there is no evidence to show soy based wires are more prone to chewing damage. Solution is to try to eliminate the rodents but I know that can be a task. A few cats, in and around machine storage can be a big help. When I was farming, my accountant always encouraged me to deduct food for my garage cats. He told me often, how much he looked forward to an auditor complaining about cat food. He was waiting but never had occasion to find one that disallowed the deduction.