I'd go with two different approaches depending on where the vehicle is parked.
- If parked outside I'd want to encourage the mice to leave the vehicle alone so I'd put bait and traps in the general area but away from the vehicle. Under the hood I'd go with things that repel mice like peppermint oil. Also I'd let the vehicle stay cold, this time of year they are seeking a warm place and a engine is warm for hours after running. Be sure to vacuum out any nests they might have left under the hood. If there is a nearby outdoor food source remove it (such as a bird feeder).
- If parked in a garage I'd seal up any access points to the garage first. Steel wool, etc, in every nook and cranny to keep the mice from getting into the garage. Don't leave any food out, including bird food, etc... unless its sealed in a can. Once the garage is sealed up I'd setup a bunch of traps on the floor of the garage to wipe out the current population. Adding repellent under the hood will also help keep them away. Leave the garage door closed as much as possible so they can't sneak in and leave some traps just in case.
- If parked outside I'd want to encourage the mice to leave the vehicle alone so I'd put bait and traps in the general area but away from the vehicle. Under the hood I'd go with things that repel mice like peppermint oil. Also I'd let the vehicle stay cold, this time of year they are seeking a warm place and a engine is warm for hours after running. Be sure to vacuum out any nests they might have left under the hood. If there is a nearby outdoor food source remove it (such as a bird feeder).
- If parked in a garage I'd seal up any access points to the garage first. Steel wool, etc, in every nook and cranny to keep the mice from getting into the garage. Don't leave any food out, including bird food, etc... unless its sealed in a can. Once the garage is sealed up I'd setup a bunch of traps on the floor of the garage to wipe out the current population. Adding repellent under the hood will also help keep them away. Leave the garage door closed as much as possible so they can't sneak in and leave some traps just in case.