Vehicle Wiring is Tasty… to Rodents!

Here at Motor Works, we specialize in solving unusual problems.  Here are two of the strangest — completely different problems with the same cause: Rodent damage.

The Problem…

Rodent damage: A wiring harness with shorted wires after being chewed by a mouse.

This wiring harness is about 6 inches too short, thanks to Mr. Mouse.

First up is a 2011 Honda CR-V.  Our client told us his parking lights weren’t working.  The brake lights, turn signals and reverse lights were all fine.  He replaced some bulbs and found a blown fuse as well.  We thought it was perhaps another shorted bulb situation, so we removed all the rear bulbs to inspect them.  But there was still a short somewhere in the system.  A quick look in the engine compartment and we had our answer.  A rodent had chewed through the wiring harness that supplies power to the driver’s side front marker light (which comes on with the parking lights).  This shorted the wires together causing the blown fuse.  We repaired the harness, replaced the blown fuse and a couple of bulbs and viola!

An Expensive Mouse…

Rodent Damage: Mouse nest on top of the engine

This mouse nest does not belong under the hood.

Rodent Damage: Damaged Wiring Harness

The fuel injector isn’t going to work too well when the wiring harness is chewed to bits.

The other was a 2009 Toyota Sienna.  This van was running rough and the Check Engine light was on.  As soon as he opened the hood, Todd had a pretty good idea what the problem was.  We found a mouse nest on top of the engine.  Mr. Mouse had snacked on the Cylinder #4 fuel injector wiring.  That, in and of itself, is fairly simple to repair just like the CR-V.

However, the short in the wiring damaged the engine control computer — which required replacement.  Ouch!

Why does this happen?

Unfortunately, rodents live everywhere we do.  They seek shelter from the weather and predators and our cars are perfect places for them to nest.  There are plenty of great nesting materials under the hood of your car (hood insulation is a popular target).  Wiring, however, is the most common item damaged.  But why is that?  The simple answer is that rodents continually gnaw on things to keep their teeth sharp.

So how do you avoid expensive repairs?  Prevention is key.  Drive your car often.  If you can, avoid parking around tall grass, near wood piles or under trees.  Keep the area around your car clear.  Take a look under your hood and look for obvious signs like rodent droppings and nests.  If you suspect something, just give us a call and we’ll help you figure it out.