Pack Rats are actually Woodrats (Mexican or Southern Plains probably in our area).
Putting out Rat bait poisons are a BEAR and DOG attractant and can kill them. These are dangerous to children as well. Make sure IF you trap that you use a bear-proof trap and put the trap in a location that is not accessible to animals or children!
They love to nest under car hoods and they chew wires, partly because they are grinding down their teeth and partly because the wire coverings can have a soy compound that must be delicious! There is a rodent tape that uses capsaicin that can be applied to the wires and/or there are various sprays and balls containing peppermint (as an example- https://a.co/d/1s6TWBR ) that can be put in and around you car.
Natural Deterrents for rodents:
Essential Oils: Peppermint, citronella, and eucalyptus oils.
Other Scents: Cayenne pepper and ammonia can also be used as deterrents.
Just place on cotton balls and put them in various entry points.