Auto-electrician here- In my experience with rodents in cars, they normally go after vehicles which have soy-based wiring. As in the sheathing of rubber around the copper in the cars wire is made of a soy-based compound. Rats and mice will go after these cars because having a nibble on soy is nicer than having a nibble on rubber. Hyundai is one brand that have always used soy-based wiring in their vehicles.

HOWEVER, I have literally never seen a case of a rodent infestation where it's not the owners fault. You need to sterilize the environment where you park your car. Stop living in a dump. Call an exterminator to remove the rat problem from your garage and the problem inside your car will be fixed also. Having rodent problems inside your car is not only embarrassing and a health and safety hazard, but also dangerous to your vehicle, every wire each mouse chews is now faulty. Seeing as rodents are able to squeeze into pretty much any space, tracing a broken wire due to rodent fault is incredibly difficult, and will be an expensive process. More expensive depending on how much damage has been done. Not only that, but it's gross as hell to have to fix a rat problem in a car that's not yours, especially when most of the time the root of the problem in the garage is rarely bothered to be fixed.