Ok here's the deal, get a couple of bars of Irish Spring bath soap (Irish Spring is key!) cut open both ends of the box & lay them in the area of concern, leave them in there box. Depending on weather might need to replace every couple months.
Found the soap trick amusing, so I did a little research.......
What Doesn't Work
• Poison Bait — Poison bait is rat food. If you want to attract birds, you put out bird food. Putting out rat poison attracts rats. They may eat the poison and die or they may collect it for their food stores. All poisons take 5-10 days to work, so even if the rat dies there is still plenty of time to do damage and “mark” your vehicle as an excellent nesting site. In most areas, there are too many rats and they breed too quickly to ever be poisoned to oblivion. In addition, bait boxes (required by law for bait used outdoors!) provide perfect places for rats to hide in and leave more of their scent. Worst of all, as the rats get sick, they are easy targets for predators. The poison in the rat’s system may also kill the very animals that eat the rats, particularly hawks and owls. See the Problems with Poison page for full details.
• Light Placed Under the Car — A light under the car is minimally effective since the rats quickly go up into the dark engine compartment. It is far more effective to open the hood and hang a light from the hood lighting up the entire engine compartment.
• Moth balls — Under NO circumstances should moth balls be used as a pack rat deterrent. They are both hazardous to human health and EPA regulated against use of this type.
• Ultrasonic devices — Rats will nest near, next to and even on top of ultrasonic devices.
You know guys I don't know, Irish Spring is key. Our parts dept stocked for a couple seasons as we had a rodent infestation at a Mercedes dealer & it cut or issues in half along with the hired help that was coming by weekly. What do you have to loose?
2 ways here. Peppermint. Sold at local hardware stores for this purpose. And another way and very effective, peanut butter and elax mixed together. They keep shitting until they dehydrate and die. Yes it works. Done it to skunks before. Be very careful if you have other pets. Then there is this,
A cat or some sticky traps with food on them. We don't get rats but I had a family of mice in the garage. Put out a few sticky traps on their access trails with a little peanut butter in the middle and the problem was solved in 2 days. Caught 12 in 48 hours. Find out where they are getting on your mav at and put them there. I had a bird that kept making a nest on top of my garage door opener. I would take it down and within a day he would start building again. I threw a sticky trap up there and the bird is gone now.
I use moth balls, well actually the moth cakes that are in the little hanging thing. I hang them in my trailer when not in use, I hang them in the engine area of my tractors, even hang them in the feed room of my barn. The lavender ones smell a little better than the regular ones but still work well. I have been using these since 1995 with great results.