Toyota used coconut oil and peanut oil in the making of the plastic coating of the wiring. There are complaints that mice have gotten in the cars and chewed the coating off the wiring thus exposing bare wires. My girlfriend experienced this issue and is dealing with her insurance company to have a new wiring harness installed in the car. The mice had gotten into the fuse block in the engine compartment and chewed at least 50% of the wire coating in the fuse block. So far the only issue she has had is she lost the low beam on the passenger side headlight. This is clearly grounds for some kind of investigation. I have talked to our local Toyota dealer and it is reported that at least 4 to 5 corollas have come in to be fixed do to mice chewing into the wiring systems.