automotive dealership or carmaker cannot void your warranty because your
vehicle has been modified with aftermarket parts. The manufacturers have to
prove that the failure was the direct result of the installed aftermarket part.
Unfortunately, too many folks have gone to a dealer to have warranty service
performed on their modified vehicle only to have the dealership refuse to cover
the defective items. The dealer tells them that the warranty is void because
aftermarket parts were installed. In such cases, they don’t even attempt to find
out whether or not the aftermarket part caused the problem. This is illegal.
Period.
Below are illustrations of aftermarket installations that would void a vehicle’s
warranty.
Example 1
You install an aftermarket electronic cruise control. While you’re driving down
the road, the cruise unit develops an internal short; this causes the accelerator
pedal to depress to the floor and over-rev the engine. After this episode the
engine develops an engine knock under acceleration or under load. The car is
still under warranty so you take it into your local dealer, and they determine that
the short in the cruise unit over-revved the engine, causing the rod bearings to
spin and thus damage the crankshaft and connecting rods. In this case, your
warranty is void because the aftermarket cruise unit caused the engine problem.
Not only are you responsible for the engine replacement, but the dealer is also
within his rights to charge you for the diagnosis. Too bad, you lose.
Example 2
You install an aftermarket air dam system to channel more air to the cold air
intake system that you installed. The air dam system causes the vehicle to
overheat because it restricts airflow over the radiator. As a result of overheating,
the engine blows a head gasket and a cylinder head is warped. The car is still
under warranty. You take it to your dealer and they determine that the
aftermarket air dam system caused the overheating and thus the cylinder head
damage and gasket failure. The carmaker is not obligated to perform any repairs
under the provisions of the warranty.
Example 3
You install a 6-foot “personal snowplow” on your SUV. The warranty expressly
states that the installation of a snowplow voids all warranty if the vehicle comes
in with frame, suspension, steering linkage, or any other damage that can be