Mice will eat the insulation off of wires. My son brought hom a Pontiac once that would not run when damp or when parked nose pointing downhill. Found a large damp mouse nest that would fall against the harness. Every green wire in that section of harness had the insulation stripped away.
85 300SD, 295K, anthracite gray, my new favorite
00 C230 Kompressor, 202K, silver bullet, hers
88 Dodge W100 4wd beast