My truck sat idle for four days. In that time a ground squirrel tore up the firewall insulation making a nest. Luckily, no wires were chewed. Be careful, it’s breeding season.
I had a Tacoma several years ago. One morning I started it and a bunch of warning icons appeared on the dash. I had Toyota come get it and was my main wiring harness chewed and a nest made by some rodent. AAA covered it and being so new they had to have a new harness shipped from Tokyo or someplace. Took a month to fix.
Years ago I had a mouse in the dash, I could hear it. It was in the blower motor, one day I quietly got in the car turned on the blower motor and turned the key. I got it, could hear it spin around, killed it. Uh oh about a week later I was getting a bad smell, had to drive with the window down, even during the winter in upstate NY. I wouldn't give anyone a ride it smelled so bad. Eventually it stopped decomposing.