My wife has a 2004 Acura TSX, which she loves greatly. But maybe due to where we live (lots of greenery), maybe due to where she parks it, maybe due to changes in the environment, we have had a few sessions of rodent damage to the wiring, a couple of them worrisomely expensive.
Rats, mice, and squirrels love to nestle around or in cars, build nests, and chew on automobile wiring. This has happened as long as I remember, but it used to be possible to see the damage, wrap some electrical tape around the bare copper, and get on with life. No longer. Wiring harnesses become increasingly complex as owners demand more and more electronic and electrical gadgets in their cars, so that the damage is often not visible, and can be found only by weird behavior on the part of engines, transmissions, lights, instruments, etc. etc. etc. And as near as I can tell, wiring harnesses are installed early in the assembly process and are often buried within the body, so often even I, who pride myself on my ability to fix anything that is broken, have to rely upon mechanics who have the proper equipment and detailed knowledge.
Our last adventure took place a couple of weeks ago, and cost us a thousand dollars and a good bit of inconvenience. My wife was parking the car in our carport, and it was not only protected from rain, but when she returned from driving it, the engine compartment was warm and snug —a rodent’s dream. A new wiring harness was required. The day after we brought the car home, there was a beautiful new nest and signs of more gnawing. I was able to tape over the bare copper and destroy the nest, we moved the the car's parking spot (many rodents can remember how to find food spatially as well as by smell), and we sprayed one of the many available “rodent repellants” in the engine compartment and on the exposed wiring. Most of these don’t work very well, and the next day it happened again. Upon looking more carefully to see where the soft and clean nest material came from, we found that the source was a mat of uncovered insulation fastened to the front of the fire wall, probably to reduce noise. What could be more convenient for our invaders?
So, we went into full war mode, complete with deep research and many traps, poisons, bought and hand made potions, noisemakers, lights, and changing parking locations. So far we are holding our own against the enemy.
One thing I learned, is that we are certainly not alone, although people seem to be a bit reluctant to talk about this problem. Maybe they feel kind of stupid, as we did since we had been through it before. A check of the internet by putting something like “rodent damage to car wiring” in one's browser results in an explosion of outrage and advice. As an example, look at this thread. The people who are writing to it are probably nice gentle family folk, who have been driven to say things such as “I want these little f***ers to stop chewing the wires in my car. Ideally, this would be because they are dead, with their bleached skulls posted on stakes around the driveway as a warning to the next generation”. The thread shows an interesting contrast between people who love rodents (they are small, cute, and fun to watch —I even got my daughter a pair of white rats as pets when she was small) and have not had their wiring eaten, and those who have.
Apparently some rodents have teeth that continually grow and they must gnaw to keep them in control. Also, apparently some car wiring insulation is made of soy, and is very tasty to rats. But although there are many commercial products available, and much advise on what to do to your automobile and cute fuzzy animals that all of a sudden have become “pests”, the problem continues.
Of course, being a simplistic engineer, I wonder why automobile manufacturers do not make cars with wiring that is repellent to rodents. It would certainly make for good advertising, and if one manufacturer did so, the others would probably be pressured to follow. Maybe rodent damage is a boon to the repair part of the automotive business. And it probably would take a bit of research to figure out what to do, since looking at the ground squirrel population in the local hills, the tree squirrels leaping happily from branch to branch, and the amount of rat and mouse poop that builds up in unused, and especially warm nooks and crannies, the rodent population is wide spread, and in parts of the world, growing. And probably rodents have been around longer than people and will continue to be here long after we are long gone.
But I consider the appetizing nature of wiring to be a serious quality flaw in at least some automobiles. I have always loved Honda (the mother of Acura) products, and in fact my wife’s car is fun to drive and a great success in all other aspects that are important to her. But we have other vehicles around, and rodents seem to give them less attention, so this may be a factor for us in determining future purchases. I asked my son who works at Tesla whether they were worrying about this problem, and he assured me that they were.