Of Rodents and Vehicle Wiring Damage . . .

By: Paul J. Bello, ACE, BCE, MBA

Introduction: Over these past years I’ve been engaged in a number of situations where rodents have chewed/gnawed upon and damaged vehicle wiring harnesses. This article presents information regarding this issue.

Years ago, manufacturers altered the materials used in wire insulation to contain soybean derivatives. This has served to make the wiring in automobiles attractive to those animals that tend to gnaw on various materials. Such animals include mice, rats and chipmunks all of which are found here in Seven Oaks.

That this has been a significant problem is well known and documented in the pest management industry. There have already been two class action lawsuits pitting consumers against auto manufacturers based in California and Hawaii in which I was engaged regarding this issue.

What initiated these cases was the extreme cost to repair/replace vehicle wiring harnesses which was many thousands of dollars and that a number of consumers learned that this was happening to many new car buyers rather than being an isolated incident as they were informed by the auto manufacturer.

Rodents continually gnaw on various materials for good reason. Their teeth constantly grow and they need to do this to keep them sharp and at an optimal length. Here in Seven Oaks, it is my experience and observation that chipmunks are the primary animal of concern for the following reasons:

• The population of chipmunks is significant.
• These animals easily access areas of vehicle wiring from beneath the car, SUV, truck, etc.
• These vehicles provide hidden and protective harborage for these animals to construct nest areas.

Once within the vehicle engine compartment these animals are hidden and difficult to detect. Therein are many wires, plastic and other such materials upon which these animals will chew or gnaw. This damage can cause electrical systems to fail and render your vehicle inoperable either in whole or in part.

How do we know we have animals entering our vehicle to nest or chew/gnaw on wires?

What we need to do is check for telltale signs of animal activity. These animals are keen on avoiding predators and will easily hide from view. However, the telltale signs of activity will include the chewed materials, the debris created from this chewing/gnawing and the deposition of their fecal materials which may be observed either beneath the vehicle or upon horizontal surfaces within the vehicle. If you suspect this is happening, you are well served to look within the engine compartment of your vehicle and/or beneath the vehicle for the aforementioned telltale signs.

What should you do to prevent this?

While some people have attempted to use naphthalene (i.e. moth balls or moth flakes) to repel these animals, this is not an optimal strategy because these animals are not repelled 100% by naphthalene and it volatilizes such that it is short lived. There are a number of efficacious rodent repellent materials commercially available. These products contain various types of pepper which these animals will avoid.

Please note that vehicles which are parked and not moved for extended periods of time are susceptible to this sort of animal activity and resulting damage. Such vehicles may be sufficiently protected via the use of repellents.

When animals have targeted a vehicle, it may be necessary to escalate the prevention to an elimination effort which will include the use of traps. If glue traps are used, these animals may be captured live and successfully released from the glue via the application of vegetable oil. Of course, we don’t want to harm these animals if there are viable options to avoid doing so.

I hope this information helps you to prevent or detect such a problem before significant damage occurs !