Its been a known problem for many years, especially with cars from the far east.In the early days it was blamed on the use of fish based glue in wiring looms. Its still quite common in continental Europe for stone/beech martens to chew wiring overnight (They are much more common in towns than their close UK relatives Pine martens)
Only about 4 years ago I had an ABS sensor wire chewed through on the continent. It was an Opel. The garage were not at all surprised. They thought it was a mouse but it could have been a marten.
I wonder if periodically spraying vulnerable wiring with windscreen washer fluid would help. It contains Bitrex.
Assuming bitrex is as bitter to rodents and mustelids as it is to humans. It might help if you have already had one rodent attack, as they are creatures of habit and may return for a second helpings. Soy Noodles with bitrex sauce. Yum Yum. But otherwise it may cause more problems than it saves due to water ingress and corrosion.
