Do you by chance live in pack rat country? Where I live they are all over the place.
When folks around here park outside, they either place a solar light under the car or in the engine compartment or leave the hood up. Pack rats don’t like light.
good advice on the rat traps, they love peanut butter or even dog food. I use a Rat Zapper around our yard.
don’t put out poison, they’ll most likely die in your Jeep. Spearmint oil does not really work either.
If you think it’s a chipmunk, peanut butter will work.
If all else fails go hit a rough washboarded up fire road for a few hours and don't air down or disconnect. Can't imagine it'll enjoy being vibrated to the point of disintegration too much.
Moth balls work but stink. They sell a device you can zip tie somewhere that uses batteries and it makes high-frequency noises that keep rats and squirrels out of your vehicles.