My neighbor recently found one in the engine bay of his brand new car, which had been brained by the radiator fan. No wires chewed… yet.

He swears that the peppermint oil strategy is working since then.

Rodents will chew wires just for the sake of chewing on something. Ask anyone who stores project vehicles for any length of time. I also had a rat or a squirrel or something chew up and spit out all my spark plug wires several years ago. It’s a good idea to keep the little blighters out of your stuff.